As filed with the Securities and Exchange Commission on
                                August 19, 1999
                          Registration No. 333-78285

                       SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C.  20549
                         POST-EFFECTIVE AMENDMENT NO. 1
                                       TO
                                    FORM S-4
                                       ON
                                   FORM S-3*
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
                                     NSTAR

                   -----------------------------------------
             (Exact name of Registrant as specified in its charter)
       MASSACHUSETTS                                  04-3466300
       -------------                                  ----------
State or other jurisdiction of                      (I.R.S. Employer
incorporation or organization)                     Identification No.)

              800 Boylston Street, Boston, Massachusetts    02199
             (Address of principal executive offices)   (Zip Code)
       Registrant's telephone number, including area code (617) 424-2000

                   -----------------------------------------
          NSTAR Dividend Reinvestment and Common Shares Purchase Plan
                   -----------------------------------------
                            (Full title of the Plan)

                             Douglas S. Horan, Esq.
                                     NSTAR
                              800 Boylston Street
                          Boston, Massachusetts 02199
                                 (617) 424-2000
                       ---------------------------------
           (Name, address and telephone number of agent for service)
                           ------------------------

                  Please send copies of all communications to:

                              David A. Fine, Esq.
                                  Ropes & Gray
                            One International Place
                          Boston, Massachusetts 02110

        Approximate date of commencement of proposed sale to the public:
     From time to time after the Registration Statement becomes effective.

  If the only securities being registered on this form are being offered
pursuant to dividend or interest reinvestment plans, please check the following
box.  [_]

  If any of the securities being registered on this form are to be offered on a
delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, other than securities offered only in connection with dividend or
reinvestment plans, check the following box.  [X]

  If this form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering.  [_]

  If this form is a post-effective amendment filed pursuant to Rule 462(c) under
the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering.  [_]

  If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box.  [_]

*  See Explanatory Note following this cover page.


                                Explanatory Note
                                ----------------

  NSTAR (the "Registrant") hereby amends its Registration Statement on Form S-4
(File No. 333-78285), effective May 14, 1999 (the "Form S-4"), by filing this
Post-Effective Amendment No. 1 on Form S-3 to the Form S-4 ("Registration
Statement") relating to the 500,000 Common Shares issuable in connection with
its Dividend Reinvestment and Common Shares Purchase Plan (the "Plan").

  Pursuant to an Agreement and Plan of Merger, dated as of December 5, 1998, as
amended and restated as of May 4, 1999 (the "Merger Agreement"), BEC Energy and
Commonwealth Energy System ("COM/Energy") will become wholly-owned subsidiaries
of the Registrant.  Also pursuant to the Merger Agreement, BEC Energy and the
Registrant have taken such or will take actions as are necessary so that BEC
Energy Common Shares are no longer issuable under the Plan.  Instead, the
Registrant's Common Shares will be issuable under the Plan in such amounts and
at such prices as adjusted pursuant to the Plan and the Merger Agreement.

  This Registration Statement relates only to the Registrant's 500,000 Common
Shares registered on the Form S-4 that will not be issued in the Merger and that
are issuable with respect to the Plan.


PROSPECTUS

                                     NSTAR

             DIVIDEND REINVESTMENT AND COMMON SHARES PURCHASE PLAN

  The Dividend Reinvestment and Common Shares Purchase Plan (the "Plan") of
NSTAR (the "Company") provides participants in the Plan with a convenient and
economical way of investing cash dividends and cash payments in additional
shares of the Company's Common Shares without payment of any brokerage
commission or service charge.  Eligible participants include:

  -  current holders of the Company's Common Shares;

  -  holders of any Preferred Shares;

  -  current residential retail electric or gas customers of the Company; and

  -  employees of the Company.

  Holders of the Company's Common Shares who elect to participate may have cash
dividends on all or some of their shares automatically invested in Common Shares
at current market prices.  Residential retail electric or gas customers may
enroll in the Plan by making an initial investment of at least $500, which will
be applied to the initial purchase of Common Shares.  An employee of the Company
who is not already a shareholder of the Company may enroll in the Plan by making
an initial investment of at least $50.

  In addition, participants in the Plan may invest monthly optional cash
payments of at least $50 per month and no more than $60,000 per calendar year,
including any initial investment, in Common Shares at current market prices.
Participants in the Plan may make automatic monthly investments for a specified
amount (not less than $50 per month) through an Automated Clearing House ("ACH")
withdrawal from their savings or checking account for purchases of shares.
Employees have the additional option of utilizing payroll deductions to make the
initial and subsequent optional cash investments.  Cash dividends on Common
Shares purchased under the Plan will be reinvested to purchase additional Common
Shares.

  The price of Common and Preferred Shares purchased from the Company for
participants in the Plan with reinvested dividends on their Common Shares and
purchases through optional cash payments, including payroll deductions, will be
100% of the average of the daily averages of the high and low sale prices for
such shares as published in the Eastern Edition of The Wall Street Journal
report on the New York Stock Exchange (NYSE) - Composite Transactions for the
last five trading days immediately preceding the date the investment is made.

  The purchase price for shares purchased on the open market will be equal to
the average price for all shares so purchased by the Agent for the applicable
investment date.

  NSTAR shares trade on the NYSE under the ticker symbol "NST."

  This Prospectus relates to 500,000 authorized and unissued Common Shares of
the Company.  It is suggested that this Prospectus be retained for future
reference.

Neither the SEC nor any state securities commission has approved or disapproved
 of these securities or determined if this Prospectus is accurate or complete.
             Anyone who tells you otherwise is committting a crime.

                 The date of this Prospectus is August__, 1999

                                       1


                             AVAILABLE INFORMATION

  NSTAR (the "Company") is subject to the informational requirements of the
Securities Exchange Act of 1934, and in accordance therewith files reports,
proxy statements and other information with the Securities and Exchange
Commission ("Commission").  Such reports, proxy statements and other reports and
information filed with the Commission can be inspected and copied at the public
reference facilities maintained by the Commission at 450 Fifth Street, N.W.,
Washington, D.C., and at the Commission's regional offices at 500 West Madison
Street, Suite 1400, Chicago, Illinois  60661, and 7 World Trade Center, 13th
Floor, New York, New York 10048.  Copies of these materials can also be obtained
through the Commission's EDGAR database, which is available through its Internet
site, at http://www.sec.gov, and at prescribed rates from the Public Reference
                           -
Section of the Commission at its principal office at 450 Fifth Street, N.W.,
Washington, D.C.  20549.  Information as of particular dates concerning trustees
and officers of the Company, their remuneration, and any material interest of
such persons in transactions with the Company is disclosed in proxy statements
distributed to shareholders of the Company and filed with the Commission.
Certain securities of the Company are listed on the New York and Boston Stock
Exchanges, where reports, proxy statements and other information concerning the
Company can also be inspected.

  The Company has filed with the Commission a registration statement on Form S-4
(herein, together with all amendments and exhibits, referred to as the
"Registration Statement") under the Securities Act of 1933, as amended.  This
Prospectus does not contain all of the information set forth in the Registration
Statement, certain parts of which are omitted in accordance with the rules and
regulations of the Commission.  For further information, reference is hereby
made to the Registration Statement.

                INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

  The following documents, previously filed by the Company with the Commission
pursuant to the Securities Exchange Act of 1934 Act (Central Index Key No.
0001085871), are incorporated into this Prospectus by reference:

  -  The Joint Proxy Statement/Prospectus covering 65,000,000 Common Shares of
     the Company, as filed with the Commission as part of the Form S-4 on May
     12, 1999.

  -  Description of Common Shares included in the Registration Statement on Form
     S-4 filed under the Securities Act, including any amendment or report filed
     for the purpose of updating such description.

  -  All documents filed by the Company pursuant to Section 13, 14 or 15(d) of
     the 1934 Act subsequent to the date of this Prospectus and prior to the
     termination of this offering of Common Shares shall be deemed to be
     incorporated by reference in this Prospectus and to be a part hereof from
     the date of filing of such documents.  Any statement contained in a
     document incorporated or deemed to be incorporated by reference herein
     shall be deemed to be modified or superseded for purposes of this
     Prospectus to the extent that a statement contained herein or in any other
     subsequently filed document which also is or is deemed to be incorporated
     by reference herein modifies or supersedes such statement.  Any such
     statement so modified or superseded shall not be deemed, except as so
     modified or superseded, to constitute a part of this Prospectus.

  The consolidated financial statements of BEC Energy included in BEC Energy's
Annual Report on Form 10-K/A for the year ended December 31, 1998, which is
incorporated by reference to the Joint Proxy Statement/Prospectus, have been
audited by PricewaterhouseCoopers LLP, independent accountants, as stated in its
report which is also included in the Annual Report.  These consolidated
financial statements are incorporated by reference in this Registration
Statement in reliance upon the report given and upon the authority of
PricewaterhouseCoopers as experts in accounting and auditing.

  The consolidated financial statements of Commonwealth Energy System
("COM/Energy") included in COM/Energy's Annual Report on Form 10-K for the year
ended December 31, 1998, which is incorporated by reference in the prospectus
included in the Joint Proxy Statement/Prospectus, have been audited by Arthur

                                       2


Andersen LLP, independent public accountants, as indicated in their reports with
respect thereto, and are included herein in reliance upon the authority of said
firm as experts in giving said reports.

  The Company hereby undertakes to provide without charge to each person,
including any beneficial owner, to whom a copy of this Prospectus has been
delivered, on the written or oral request of any such person, a copy of any or
all of the documents incorporated herein by reference, other than exhibits to
such documents unless specifically incorporated by reference in such documents.
Requests for such copies should be directed to Investor Relations, NSTAR, 800
Boylston Street, Boston, MA  02199, telephone: (617) 424-2000.

                                  THE COMPANY

  The Company is a holding company which owns BEC Energy and Commonwealth Energy
System ("COM/Energy") and is engaged, through its subsidiaries, in the
distribution of electric energy and gas as well as in non-utility businesses,
such as telecommunications.  The Company is an energy delivery company that
services approximately 1,040,000 electric customers in 81 communities in eastern
Massachusetts and approximately approximately 240,000 gas customers in 51
communities in eastern Massachusetts.  NSTAR's electricity and gas utility
subsidiaries consist of  Boston Edison Company, Harbor Electric Company,
Commonwealth Electric Company, Cambridge Electric Light Company, Canal Electric
Company, Medical Area Total Energy Plant, Inc., and Commonwealth Gas Company.

  The Company was organized in 1999 as a business trust under the laws of The
Commonwealth of Massachusetts.  Its principal executive offices are located at
800 Boylston Street, Boston, Massachusetts 02199, and its telephone number is
(617) 424-2000.

                            DESCRIPTION OF THE PLAN

  The following is a question and answer statement of the provisions of the
Company's Dividend Reinvestment and Common Shares Purchase Plan (the "Plan").

PURPOSE

1. What is the purpose of the Plan?

  The purpose of the Plan is to provide participants with a convenient and
economical way of investing cash dividends in Common Shares of the Company as
well as optional cash payments in shares of Common Shares without payment of any
brokerage commission or service charge.

FEATURES AND BENEFITS

2. What are the features of the Plan?

  Participants in the Plan may:

  -  reinvest all or part of their Common or Preferred dividends, conveniently
     and economically

  -  purchase additional Common Shares with cash, as often as monthly ($50
     minimum-$60,000 annual maximum)

  -  use electronic funds transfer from their bank account for automatic monthly
     purchase of shares

  -  sell shares with a simple phone call

  -  deposit share certificates in safekeeping (for shares enrolled in the Plan)

                                       3


  -  pay no brokerage commissions on share purchases (participants are
     responsible for paying the applicable tax on such commissions or service
     charges paid by the Plan)

  -  receive a regular statement of account with a complete record or each
     transaction

     Full investment of funds is possible under the Plan because the Plan
  permits fractional shares, as well as full shares, to be credited to
  participants' accounts. In addition, dividends in respect of such fractions,
  as well as full shares, will be credited to participants' accounts.

ADMINISTRATION

3. Who administers the Plan for participants?

  BankBoston, N.A. (the "Agent") administers the Plan for participants,
maintains records, sends statements of account to participants following the
completion of any activity affecting the balance of an account and performs
other duties relating to the Plan.  Correspondence to the Agent should be sent
to BankBoston, N.A., c/o EquiServe, L.P., Shareholder Services Division, P.O.
Box 8040, Boston, MA 02266-8040.  The Agent may be contacted by calling 1-800-
338-8446 or for the Telecommunication Device for the Deaf (TDD) by calling 1-
800-952-9245.

PARTICIPATION

4. Who is eligible to participate in the Plan?

Shareholders:

  All holders of record of Common or Preferred Shares are eligible to
participate in the Plan.  All purchases under the Plan will only be made in
Common Shares.  Beneficial owners of any of the Company's  shares whose shares
are registered in names other than their own (e.g., a broker or bank nominee)
must arrange participation with the record holder.  To facilitate this, the
Company has instructed the Agent to make arrangements with major depositories to
provide for brokers and bank nominees to participate on a dividend-by-dividend
basis on behalf of beneficial owners.  If for any reason a beneficial owner is
unable to arrange participation with his broker or bank nominee, he must become
a record holder by having the shares registered in his own name.

Customers and Employees (Non-Shareholders):

  Residential retail electric or gas customers of record of the Company and
employees of the Company, who are not already  shareholders of the Company, may
participate in the Plan without first becoming shareholders of the Company.  See
Question 8 for information concerning enrollment in the Plan by customers and
Question 13 for information concerning payroll deductions by participating
employees.  Once a customer or an employee joins the Plan, their participation
in the Plan is no different from that of any shareholder in the Plan.

PARTICIPATION BY SHAREHOLDERS

5. How does a shareholder enroll in the Plan?

   A shareholder may enroll in the Plan at any time by calling the Agent at 1-
800-338-8446 or completing the Authorization Form and returning it to the Agent.
Those shareholders who do not wish to participate in the Plan will continue to
receive dividends, as declared.

6. What does the shareholder Authorization Form provide?

                                       4


  The shareholder Authorization Form allows each shareholder to decide the
extent to which such shareholder wants to participate in the Plan. By checking
the appropriate box on the Authorization Form, shareholders may indicate whether
they want to:

  -  reinvest dividends paid on all or some of the Common or Preferred Shares
     registered in his name that are not already held in the Plan and
     participate in the Plan by making optional cash payments; or

  -  participate in the Plan only by making optional cash payments.

See Question 18 regarding reinvestment of dividends on shares held in the Plan.

7. Can a shareholder place shares held in certificate form in Safekeeping?

   Any shareholder who holds Common Shares in certificate form may transfer
those shares into the Plan in book entry form (i.e., place those shares in
"Safekeeping" as described below), but only by joining the Plan and with the
understanding that dividends on those shares will be reinvested like any other
shares held in the Plan. If a shareholder is not already a member of the Plan,
he will be required to complete an Authorization Form prior to transferring his
certificates. Safekeeping is not available, however, for shares of Preferred or
Preference Stock.

   The certificates of Common Shares submitted for Safekeeping will be added to
the participant's account balance and will appear in subsequent statements.
Certificates should be sent to BankBoston, N.A., c/o EquiServe, L.P.,
Shareholder Services Division, P.O. Box 8040, Boston, MA 02266-8040 by
registered or certified mail with a letter of instruction notifying the Agent of
a desire to transfer shares into Safekeeping. Certificates need not be endorsed
for deposit purposes.

PARTICIPATION BY CUSTOMERS AND EMPLOYEES

8. How does a customer of record enroll in the Plan?

   A residential retail electric and/or gas delivery customer of record of the
Company may enroll in the Plan at any time by completing a customer Enrollment
Form. To request an Enrollment Form, please contact the Agent at 1-800-338-8446
or the Company's Investor Relations Department at 800 Boylston Street, Boston,
MA 02199 or by phone (617) 424-2000. The Company will mail a Prospectus and an
Enrollment Form to the customer, but only at a Massachusetts address. The
customer of record would then complete the Enrollment Form, certifying the
accuracy of information, and return it with a check for an initial investment
amount of at least $500. Checks must be in U.S. dollars, drawn on a U.S. bank.
Checks should be made payable to BankBoston, N.A. and returned with the
Enrollment Form to BankBoston, N.A., c/o EquiServe, L.P., Shareholder Services
Division, P.O. Box 8040, Boston, MA 02266-8040 in the return envelope provided.
Initial investments that are not accompanied by a completed Enrollment Form will
be returned to the individual.

  As a customer, you must meet the following four conditions to be eligible to
participate in the Plan:

  -  You must be the customer of record.  In other words, your name must appear
     on the electric and/or gas billing account of one of NSTAR's electric or
     gas utility subsidiaries.  No other family member or persons residing at
     this address will be allowed to participate; however, other persons may be
     included in joint ownership with a customer of record.

  -  You must be a residential electric or gas customer.

  -  You must be at least 18 years of age.

  -  Have a mailing address within the Commonwealth of Massachusetts.

  Upon receiving the Enrollment Form and establishing an account, the Plan Agent
will make the initial investment on the first business day of the month in
Boston, Massachusetts (an "Investment Date") provided such initial investment is
received at least 2 business days prior to an Investment Date.  If initial
investments are

                                       5


received later than 2 business days prior to an Investment Date, those funds
will be held until the next monthly Investment Date.

9. How does an employee enroll in the Plan?

   Employees may enroll in the Plan by means of the payroll deduction option as
described in Question 13.  Employees who are also residential retail customers
of record may enroll as customers as described above, instead of enrolling
through payroll deduction.

OPTIONAL CASH PAYMENTS

10. Who is eligible to make optional cash payments?

   All participants are eligible to make optional cash payments.  Employees who
have enrolled in the Plan may also make optional cash payments through payroll
deductions as described in Question 13.  There is no requirement to make a
monthly investment.

   Optional cash payments may be invested by the use of the cash payment form
attached to the statement sent to participants by the Agent.  Optional cash
payments should be made in the form of checks or money orders in U.S. funds,
drawn on a U.S. bank.  Checks should be made payable to BankBoston, N.A. and
should be sent to BankBoston, N.A, c/o EquiServe, L.P., Shareholder Services
Division, P.O. Box 9041, Boston, MA 02205-9835.  Payments to any other address
do not constitute valid delivery.

   Under no circumstances should optional cash payments by customers be included
in the payment of monthly electric and/or gas bills or sent to the Company.

   An optional cash payment may be made by a shareholder participant when
enrolling by enclosing a check with the completed Authorization Form.  Checks
should be made payable to BankBoston, N.A., and returned along with the
Authorization Form to the address above.

   Participants in the Plan may make automatic monthly investments of a
specified amount (not less than $50 per month) through an Automated Clearing
House ("ACH") withdrawal from their savings or checking account. Once automatic
monthly deductions are initiated, funds will be drawn from their designated bank
account on the 25th of each month and will be invested in Common Shares on the
next investment date. Enrollment forms for the Automatic Monthly Investment
Program may be obtained by calling the Agent at 1-800-338-8446.

   Participants can change or stop the automatic payments by completing and
returning a new form to the Agent.

   If a shareholder participant chooses to participate by optional cash payments
only, the Agent will pay cash dividends on any shares held in certificate form
in the usual manner and will apply any optional cash payment received from the
participant prior to the Investment Date to the purchase of additional Common
Shares for the participant's account.  However, dividends payable on Common
Shares credited to the account of the participant under the Plan, including
shares held in Safekeeping, will be automatically reinvested in additional
Common Shares.

11. What are the limitations on making optional cash payments?

   The option to make cash payments is available to each participant at any
time. With the exception of the initial investment by customers joining the
Plan, optional cash payments by a participant cannot be less than $50 per month
and cannot exceed a total of $60,000 per calendar year. The same amount of money
need not be sent each month and there is no obligation to make an optional cash
payment each month. For customers joining the Plan, there is an initial cash
investment required of at least $500 as described in Question 8.

12. When will optional cash payments received by the Agent be invested?

                                       6


  Optional cash payments will be invested monthly on the first business day of
the month in Boston, Massachusetts, provided the optional cash payment is
received at least two business days prior to an Investment Date.  If optional
cash payments are received later than two business days prior to an Investment
Date, those funds will be held until the next monthly Investment Date.  See
Question 15 for transactions involving open market purchases.  Under no
circumstances will interest be paid by the Company or the Agent on optional cash
payments.  Any funds held by the Agent will be returned upon the participant's
written request which must be received at least two business days before an
Investment Date.  Any optional cash payments received of less than $50 per month
(or less than $500 for an initial customer investment) or in excess of $60,000
per calendar year will be returned to the participant.  The Company will not
waive the maximum investment a participant may contribute under the Plan per
calendar year.

  In the event that any deposit of money (by check, money order or ACH debit
transaction) is returned to the Agent unpaid for any reason, the Agent will
consider the request for investment of such money null and void and shall
immediately remove from the participant's account any shares or fraction thereof
which may have been credited to that account.  The Agent shall be entitled to
sell these shares to satisfy any amount of such money uncollected.  If the net
proceeds of the sale of such shares are insufficient to satisfy the balance of
such moneys which are uncollected, the participant shall be liable for any such
deficiency and the Agent shall be entitled to sell additional shares from the
participant's account to satisfy the uncollected balance.  In addition, a $25.00
fee will be charged for any such deposit returned unpaid.

PAYROLL DEDUCTIONS FOR EMPLOYEES

13. How do employees of the Company elect to participate through payroll
    deductions?

  Employees can enroll in the Plan and make optional cash payments through
payroll deductions by completing the Payroll Deduction Authorization Form
(available from the Company Payroll Department), which authorizes the Company to
deduct any amount specified by the employee, but at least $50 per month and no
more than $60,000 per calendar year, from the employee's regular paycheck.  In
order to comply with this monthly minimum requirement, weekly paid employees
must specify a weekly deductible amount of at least $12.50.  The Agent will
invest the accumulated payroll deductions in Common Shares monthly on each
optional cash Investment Date.  If the employee has made optional cash payments
which in addition to the payroll deductions during such calendar year exceed
$60,000, the Agent will return to the employee the excess received over $60,000.

  In order to commence payroll deductions, the Payroll Deduction Authorization
Form must be received by the Company's Payroll Department two weeks before the
payday on which the employee will expect to see the deductions begin.  An
employee for whom payroll deductions have already been started may change the
amount of the employee's deductions by submitting a new Payroll Deduction
Authorization Form, or other appropriate form which may be obtained from the
Company, two weeks before the payday on which the employee wishes to have the
amount changed.  No interest will be paid by the Company or the Agent on payroll
deductions.

DIVIDEND REINVESTMENT

14. When will dividends be invested?

  Cash dividends on Common Shares are generally payable on the first day of
February, May, August and November.  The Investment Date for these dividends
will be on the payment date or, if that date is not a business day in Boston,
Massachusetts, on the next following business day.  See Question 15 for
Investment Date for open market purchases.

  If the Authorization Form signed by the shareholder entitled to a dividend is
received by the Agent on or before the record date for a particular dividend
(usually the 10th day of the month prior to the payment date), that dividend
will be used to purchase additional Common Shares for the shareholder on the
current dividend payment date.  If the Authorization Form is received by the
Agent after the record date for a particular dividend, then the reinvestment of
dividends will not begin until the next following applicable dividend payment
date.  For example, in order to invest the quarterly Common Shares dividend
payable November 1 with a record date of October 10, a


                                       7


shareholder's Authorization Form must be received by the Agent no later than
October 10. If the Authorization Form is received after October 10 the dividend
payable on November 1 will be paid in cash, and the shareholder's participation
in the Plan will begin with the next dividend payment date (February 1). See
Questions 12 and 13 for information concerning the investment of optional cash
payments and payroll deductions.

PURCHASES

15. What is the source of shares purchased under the Plan?

    Common Shares of the Company will be obtained through purchases of newly-
issued shares from the Company or through open market purchases of shares.  If,
however, the average of the daily averages of the high and low sale prices for
Company Common Shares as published in the Eastern Edition of The Wall Street
Journal report on the New York Stock Exchange - Composite Transactions for the
last five trading days immediately preceding a purchase date is less than $15,
the Company must direct the Agent to make purchases on the open market. The
Company may change its determination that Common Shares will be purchased
directly from the Company or on the open market no more than once every three
months and only if the Company's Board of Trustees or Chief Financial Officer
determines such change is necessary.

    When the Agent purchases shares in the open market, purchases may begin in
advance of the dividend payment date.

16. How many Common Shares will be purchased for participants?

    The number of shares to be purchased depends on the amount of the
participant's dividend, including dividends on shares credited to the
participant's account under the Plan, the amount of any optional cash payments
or payroll deductions and the purchase price of Common Shares on the applicable
Investment Date.  Each participant's account will be credited with that number
of shares, including fractions, equal to the total amount to be invested divided
by the applicable purchase price.  In the event of open market purchases, shares
will not be allocated to participants' accounts until the date on which the
Agent has settled purchases of sufficient shares for all participants.

17. What will be the price of Common Shares purchased under the Plan?

    In the event shares are purchased by the Agent on the open market, the
purchase price to participants will be equal to the average price for all shares
so purchased on the open market.  Any brokerage commissions on open market
purchases will be paid by the Company at no cost to participants.  However, any
brokerage commissions paid by the Company on a Participant's behalf are treated
as distributions subject to income tax in the same manner as dividends.

    In the event that shares are purchased from the Company, the purchase price
will be 100% of the average of the daily averages of the high and low sale
prices for such Common Shares as published in the Eastern Edition of The Wall
Street Journal report on the New York Stock Exchange - Composite Transactions
for the last five trading days immediately preceding the applicable Investment
Date.

18. May I have dividends on shares held in the Plan sent directly to me?

    No.  The purpose of the Plan is to provide the participant with a convenient
method of purchasing Common Shares and having the dividends on those shares
reinvested.  Accordingly, dividends paid on shares held in the Plan will be
automatically reinvested in additional Common Shares.  Participants in the Plan
do not pay a brokerage fee or service charge in connection with any purchase of
shares for their account under the Plan.  A participant may, of course, receive
certificates for full shares accumulated in the participant's account under the
Plan at any time by sending a written request to BankBoston, N.A., c/o
EquiServe, L.P., Shareholder Services Division, P. O. Box 8040, Boston, MA
02266-8040.  A withdrawal/termination form is provided on the reverse


                                       8


side of the account statement for this purpose. As an alternative, participants
may request a certificate be issued to them in the same registration by calling
EquiServe, L.P. at 1-800-338-8446. When certificates are issued to the
participant, future dividends on these shares will be treated in accordance with
the instructions indicated on the participant's Authorization Form. Participants
who joined the Plan initially as customers or as employees through payroll
deductions will need to complete a new Authorization Form to change their
enrollment if they wish to receive cash dividends on the newly issued
certificate shares.

COSTS

19. Are there any expenses to participants in connection with purchases under
    the Plan?

    No.  There are no service charges related to purchases and all costs of
administration of the Plan are paid by the Company.  There are costs associated
with sales from the Plan, however, as described under Question 26.

REPORTS TO PARTICIPANTS

20. How will participants be advised of their purchase of shares?

    As soon as practicable after each purchase a participant will receive a
statement of account.  These statements are a participant's continuing record of
purchases made through the Plan and should be retained for tax purposes.  In
addition, each participant will receive copies of the same communications sent
to every other shareholder, including the quarterly reports, annual report,
notice of shareholders' meeting and proxy statement, and income tax information
for reporting dividends paid.

    Participants should be aware that it is important to retain all statements
received because, generally, a fee is incurred when requesting the Agent to
supply past history.

DIVIDENDS

21. Will participants be credited with dividends on shares held in their
    accounts under the Plan?

    Yes.  The Company pays dividends, as declared, to the record holders of all
its Common Shares, whether the shares are held in accounts under the Plan or
not.  As the record holder for participants, the Agent will receive dividends
for all shares credited to participants' accounts on the record date.  It will
credit such dividends to participants on the basis of full and fractional shares
held in their accounts, and will reinvest such dividends in additional shares.

CERTIFICATES FOR SHARES

22. Will certificates be issued for Common Shares purchased through the Plan?

    Normally, certificates for Common Shares purchased under the Plan will not
be issued to participants. The number of shares credited to an account under the
Plan will be shown on the participant's statement of account. This additional
service protects against loss, theft or destruction of certificates.

   Certificates for any number of shares up to the number of full shares
credited to an account under the Plan will be issued upon written request of a
participant who wishes to remain in the Plan. A withdrawal/termination form is
provided on the reverse side of the account statement for this purpose. This
request should be mailed to BankBoston, N.A., c/o EquiServe, L.P., Shareholder
Services Division, P.O. Box 8040, Boston, MA 02266-8040. As an alternative,
participants may request a certificate be issued to them by calling EquiServe,
L.P. at 1-800-338-8446.

   Shares credited to the account of a participant under the Plan may not be
pledged.  A participant who wishes to pledge such shares must request that
certificates for such shares be issued in the participant's name.

  Certificates for fractional shares will not be issued under any circumstances.

                                       9


23. In whose name will an account be maintained and certificates registered when
    issued?

    An account for a participant will be maintained by the Agent in the
participant's name as shown on the Company's records at the time the participant
enters the Plan.  When issued, certificates for full shares will be registered
in the account name.

    Upon written request, certificates also can be registered and issued in
names other than the account name subject to compliance with any applicable laws
and the payment by the participant of any applicable taxes, provided that the
certificate or stock power assignment bears the signature of the participant and
the signature is guaranteed by a financial institution that is a member of a
Stock Transfer Association approved medallion program such as STAMP, SEMP or
MSP.

CHANGING METHOD OF PARTICIPATION AND WITHDRAWAL

24. How does a participant change his method of participation?

    A participant may change his method of participation at any time by calling
the Agent, or by completing an Authorization Form and returning it to the Agent,
or by submitting a written request to BankBoston, N.A., c/o EquiServe, L.P.,
Shareholder Services, P.O. Box 8040, Boston, MA 02266-8040.  The Authorization
Form must be received by the Agent on or before the record date of a dividend in
order for the change to be effective for such dividend.

25. May a participant withdraw from the Plan?

    Yes.  The Plan is entirely voluntary and a participant may withdraw at any
time.

     If the request to withdraw is received by the Agent on or before the record
date for any particular dividend, the amount of the dividend and any optional
cash payment, including payroll deductions, which would otherwise have been
invested on such Investment Date will be paid as soon as practicable to the
withdrawing participant.  Thereafter all dividends will be paid in cash to the
shareholder.  A shareholder or eligible employee may elect to re-enroll in the
Plan at any time by submitting to the Agent a completed Authorization Form.

26. How does a participant withdraw from the Plan?

    In order to withdraw from the Plan, a participant must notify the Agent in
writing of a withdrawal request.  A withdrawal/termination form is provided on
the reverse side of the account statement for this purpose.  This notice should
be addressed to BankBoston, N.A., c/o EquiServe, L.P., P.O. Box 8040, Boston, MA
02266-8040  When a participant withdraws from the Plan or upon termination of
the Plan by the Company, certificates will be issued for whole shares credited
to the participant's account under the Plan and a cash payment will be made for
any fraction of a share.

    Upon withdrawal from the Plan, the participant may request in writing that
all of the shares, both whole and fractional, credited to the participant's
account in the Plan be sold. If a participant requests that shares be sold, the
sale will be made by the Agent in the market within five trading days after
receipt of the request. The participant will receive the proceeds of the sale
less any brokerage commission, transfer tax and a small transaction fee. The
transaction fee will be equal to 5% of the total sales value with a $1 minimum
and $15 maximum charge.

  Participants should be aware that prices of Common Shares may fall during the
period between a request for sale, its receipt by the Agent, and the ultimate
sale in the open market within five business days after receipt.  This risk
should be evaluated by the participant and is a risk to be borne solely by the
participant.  No redemption check will be mailed to the participant prior to
settlement of funds from the brokerage firm which usually is three business days
after the sale of shares.  The participant's interest in any fractional share
held at termination will be paid in cash at the then current market value of the
Common Shares when the transaction is processed.

                                      10


Participants should maintain their statement of account as their record for
income tax purposes. Information regarding the redemption of shares will be
furnished to the Internal Revenue Service.

27. How does an employee participating through payroll deductions withdraw from
    the Plan?

    In addition to the withdrawal request sent to the Agent, a participating
employee who has elected payroll deductions must notify the Company's Payroll
Department in writing to discontinue the payroll deductions sufficiently in
advance of the employee's next paycheck to allow processing (normally at least
two weeks).  If the notice is so received by the Company, no further payroll
deductions will be made and the accumulated amount withheld during the period
after the last investment date and before the withdrawal request is processed
(even if less than the $50 monthly minimum amount) will be invested on the next
month's Investment Date, unless prior to such Investment Date the employee
notifies the Company's Payroll Department in writing that such employee wants to
receive all withheld amounts in cash.

    If an employee has withdrawn from the Plan with the Agent prior to
discontinuing their payroll deduction, the accumulated amount withheld will be
paid to the employee in cash.

28. What happens to a fraction of a share when a participant withdraws from the
    Plan?

    When a participant withdraws from the Plan a cash payment representing any
fraction of a share will be mailed directly to the participant.  The cash
payment will be based on the then current market price of the Common Shares when
the transaction is processed.

29. May an employee terminate participation through payroll deductions and still
    remain in the Plan?

    Yes.  An employee who terminates payroll deductions may leave shares in the
Plan.  Dividends paid on shares left in the Plan will continue to be
automatically reinvested in the account.  The participant may also continue to
make optional cash payments.

30. May a participant who has withdrawn from the Plan rejoin?

    Generally, a shareholder, customer or employee that has withdrawn may again
become a participant at any time.  However, the Company reserves the right to
reject any former participant on the grounds of excessive withdrawals.

OTHER INFORMATION

31. What happens when a participant sells or transfers all of the certificate
    shares registered in the participant's name?

    If a participant disposes of all shares registered in the participant's name
in certificate form, the Agent will continue to reinvest the dividends on the
shares credited to the account under the Plan.  As long as there are shares
credited to a participant's account, that participant will remain a participant
in the Plan until the participant notifies the Agent of a desire to terminate
their participation.  However, if a participant has only a fractional share
credited to the participant's account under the Plan on the record date for any
cash dividend on the Common Shares, the Company reserves the right not to
reinvest any additional dividends on such fractional share.  If the Company
exercises this right, the participant will receive a cash adjustment
representing such fraction of a share plus the amount of the cash dividend on
such fraction.  The cash payment for the fractional share will be based on the
then current market price of the Common Shares when the transaction is
processed.

32. What happens if the Company declares a share split?

    Any split shares distributed by the Company on shares credited to the
account of a participant under the Plan will be added to the participant's
account. Split shares distributed on shares held by participants outside the
Plan will be mailed to such participants in the same manner as to shareholders
who are not participating in the Plan.

                                      11


33. How will a participant's shares held under the Plan be voted at meetings of
    shareholders?

    If shares registered in the name of a participant in the Plan are voted by
the participant on any matter submitted to a meeting of shareholders, the Agent
will vote any shares held in the participant's account under the Plan in
accordance with the participant's proxy for the shares registered in the
participant's name. If the participant desires to vote in person at the meeting,
a proxy for shares credited to the participant's account under the Plan may be
obtained upon written request received by the Agent at least 15 days before the
meeting.

    If no instructions are received on a returned proxy card, properly signed,
or other permitted method for voting with respect to any item to be acted upon
at the meeting, all of a participant's shares (those registered in the
participant's name, if any, and those credited to the participant's account
under the Plan) will be voted in accordance with the recommendations of the
Company's management with respect to that item. If a participant does not vote
his shares by returning a properly signed proxy card or properly completing an
alternative permitted method for voting , none of the participant's shares will
be voted unless the participant votes in person.

34. What are the federal income tax consequences of participation in the Plan?

    a.  Reinvested Dividends

    Reinvested dividends will be subject to federal income tax as follows. A
participant will realize, on the Investment Date, a taxable dividend in an
amount equal to the number of shares purchased times:

- --in the case of shares purchased on the open market, the average price for all
shares so purchased on the open market on a given Investment Date, including the
amount of any commissions paid by the Company on such shares; and

- -- in the case of shares purchased from the Company, the average of the daily
high and low sale prices of the shares reported as New York Stock Exchange -
Composite Transactions for the Investment Date.

    The tax basis of shares purchased with reinvested dividends is the amount
taxed as a dividend upon the receipt of such shares (which includes the amount
of any commissions paid by the Company in the case of shares purchased on the
open market).

    In the case of a shareholder who is subject to backup withholding tax on
dividends under the Plan, or a foreign shareholder whose dividends are subject
to United States income tax withholding, the amount of the tax to be withheld
will be deducted from the amount of the dividends and only the reduced amount
will be reinvested in Common Shares.

    b.  Optional Cash Payments

    Participants who purchase shares with optional cash payments realize no
taxable income at the time of the purchase, except that any commissions paid by
the Company on the purchase of such shares will be taxed as a dividend. An
employee of the Company who participates in the payroll deduction aspect of the
Plan will have the same federal income tax obligations with respect to the
payroll deductions as he would have had if the money were not deducted from his
paycheck. A participating employee will be treated for federal income tax
purposes as having received the full amount of his salary for that pay day even
though he actually received that amount less the payroll deductions.

    The tax basis of shares purchased with optional cash payments is the amount
paid for the shares, including amounts paid for brokerage commissions.

    c.  General

    A participant's holding period for shares acquired pursuant to the Plan will
begin on the day following the applicable Investment Date.

    A participant will not realize any taxable income solely as a result of
receiving a certificate for whole shares credited to the participant's account,
either upon request for the certificates for certain of those shares or upon
withdrawal from or termination of the Plan.

                                      12


  A participant will recognize gain or loss when shares are sold, whether such
sale is pursuant to a request upon the participant's withdrawal from the Plan or
takes place after withdrawal from or termination of the Plan.  A participant
will also recognize a gain or loss upon receipt of a cash payment for a fraction
of a share.  In either event, the amount of the gain or loss will be the
difference between the amount which the participant receives for the shares or
fraction of a share and the tax basis thereof.

  All participants are urged to consult their own tax advisors to determine the
particular federal, state, and/or local tax consequences that may result from
their participation in the Plan and the subsequent disposal by them of shares
purchased pursuant to the Plan.  The income tax consequences for participants
who do not reside in the United States will vary from jurisdiction to
jurisdiction.

35. May the Plan be changed or discontinued?

  While the Company hopes to continue the Plan indefinitely, the Company
reserves the right to amend, suspend, modify or terminate the Plan at any time.
Notice of any such amendment, suspension, modification or termination will be
sent to participants.

36. What is the liability of the Company and the Agent under the Plan?

  The Company and the Agent administering the Plan will not be liable for any
act done in good faith or for any omission to act in good faith, including,
without limitation, any claim of liability arising out of the failure to
terminate a participant's account upon such participant's death prior to receipt
of notice in writing of such death.

  The participant should recognize that neither the Company nor the Agent can
assure a profit or protect against a loss on the shares purchased under the
Plan.

37. Who interprets and regulates the Plan?

  The Company reserves the right to interpret and regulate the Plan as may be
necessary or desirable in connection with the operation of the Plan.

                                USE OF PROCEEDS

  To the extent shares are purchased in the open market, the Company will not
receive any of the proceeds. If shares are issued directly by the Company,
although the Company does not know whether all of the 500,000 Common Shares
covered by this Prospectus will be sold or the exact prices at which they will
be sold, the minimum aggregate proceeds if all such shares are sold will be
$7,500,000 before deducting expenses of the offering. The proceeds of any sales
will be used for capital expenditures for extensions, additions, and
improvements to the Company's electric energy and gas distribution networks, for
the payment of debt balances of the Company and for other general corporate
purposes.

                             DESCRIPTION OF SHARES

Authorized Capital

  The shares of the Company consist of (1) Common Shares, par value $1 per
share, of which 100,000,000 shares have been authorized; and (2) 10,000,000
preferred shares, each with a par value of $1.00.  Following completion of the
merger of BEC Energy and COM/Energy into the Company, the Company expects to
have approximately 61,500,000 Common Shares issued and outstanding, and no
preferred shares issued and outstanding.  The NSTAR Board of Trustees may issue
the authorized Common Shares and/or preferred shares at any time without
obtaining further consent of the shareholders or any approvals from the
Massachusetts Department of Telecommunications and Energy.  The Company may
issue its shares for money, services or property, or as a distribution to
shareholders.  Further, it may issue its shares upon terms determined by the
Company's Board of Trustees  in its absolute discretion.

                                      13


Common Shares

  Subject to the powers, preferences, and rights of any preferred shares or
series thereof that may issue, having any preference or priority over, or rights
superior to, the Common Shares and except as otherwise provided by law, the
holders of the Common Shares will have the exclusive right to vote for the
election of Trustees and on all other matters submitted to the shareholders for
action.  Each Company Common Share will entitle its holder to one vote.  Holders
of Company Common Shares will not have cumulative voting rights in the election
of Trustees. Dividends on Common Shares may be declared and paid as the Board of
Trustees may determine.  Holders of the Common Shares have no conversion or
preemptive rights and are not liable to further call or assessment.

Preferred Shares

  The Company may issue preferred shares in one or more series.  The Board of
Trustees will determine which, if any, designations, preferences, voting rights
and other special rights will attach to the preferred shares.  The Company may
issue preferred shares with various rights that could be used to deter takeover
attempts if the Board of Trustees decides that it would be advisable to do so.
The Company may also issue other equity and debt securities in the future.

Massachusetts Anti-Takeover Laws and Various Provisions of NSTAR's
Organizational Documents

  The Company's Declaration of Trust and Bylaws contain provisions which may
serve to deter takeovers.  Its Declaration of Trust establishes a classified
board of trustees and requires a supermajority vote of the disinterested
shareholders to approve various business transactions with shareholders who own
more than 5% of the company.

Interested Shareholder Statute

  The Company is also governed by a state interested shareholder statute,
Chapter 110F of the Massachusetts General Laws.  Chapter 110F prohibits the
Company from entering into a business combination with an interested shareholder
for a period of three years after the date of the transaction in which the
person became an interested shareholder.  An interested shareholder includes an
person who, together with his or her affiliates or associates, collectively
acquires 5% or more of the Company's outstanding voting shares.  A business
combination includes a merger, a sale of shares or assets, and various other
transactions in which an interested shareholder receives a financial benefit.
Chapter 110F does not apply if:

  -  the interested shareholder obtains the approval of the Company's Board of
     Trustees before acquiring 5% or more of the Company's outstanding voting
     shares; or

  -  the interested shareholder acquires 90% of the Company's non-affiliate held
     voting shares at the time he or she first acquires more than 5% of the
     voting shares; or

  -  both the Company's Board of Trustees and non-interested shareholders
     holding two-thirds of the company's voting shares approve the transaction.

Chapter 110F allows Massachusetts companies to elect not to be governed by its
provisions.  This election, however, would not be effective for 12 months and
would not apply to transactions with any person who became an interested
shareholder before the election.  The Company has not made this election and is
therefore subject to the provisions of Chapter 110F.

Control Share Acquisition Statute

  The NSTAR bylaws include a provision excluding the Company from the
applicability of Chapter 110D of the Massachusetts General Laws.  Chapter 110D
regulates the acquisition of control shares.  A control share acquisition is the
acquisition of shares which, when added to shares already owned, would allow the
acquiring person to vote at least 20% of an entity's stock.  Under Chapter 110D,
shares acquired in this type of transaction would have no voting rights unless a
majority of non-interested shareholders specifically voted to grant the
acquiring person voting rights for these shares.  In general, the acquiring
person and officers and employee-


                                      14


trustees of the Company are not permitted to vote on whether these voting rights
should be granted. The Company's Board of Trustees may amend the Company's
bylaws at any time to subject the Company to this control share acquisition
statute on a going-forward basis.

                                 LEGAL OPINIONS

  The validity of the Common Shares is being passed upon for the Company by
Ropes & Gray, One International Place, Boston, Massachusetts, counsel for the
Company.  Thomas G. Dignan, Jr., a partner of Ropes & Gray, is a trustee of the
Company.

                                    EXPERTS

     The consolidated financial statements of BEC Energy included in BEC
Energy's Annual Report on Form 10-K/A for the year ended December 31, 1998 have
been audited by PricewaterhouseCoopers LLP, independent accountants, as stated
in its report which is also included in the Annual Report.  These consolidated
financial statements have been incorporated by reference in this Prospectus  in
reliance upon the report and upon the authority of PricewaterhouseCoopers LLP as
experts in accounting and auditing.

  The consolidated financial statements and schedules of COM/Energy incorporated
by reference in this joint proxy statement/prospectus have been audited by
Arthur Andersen LLP, independent public accountants, as indicated in their
reports with respect to the financial statements, and are included in this
Prospectus in reliance upon the authority of Arthur Andersen LLP as experts in
giving such reports.

  With respect to the unaudited interim consolidated financial information of
BEC Energy for the periods ended March 31, 1999 and 1998, incorporated by
reference in this Prospectus, PricewaterhouseCoopers LLP has reported that they
have applied limited procedures in accordance with professional standards for a
review of such information.  However, their separate reports included in BEC
Energy's Quarterly Reports on Form 10-Q for the quarter ended March 31, 1999,
and incorporated by reference herein, state that they did not audit and they do
not express an opinion on that interim consolidated financial information.
Accordingly, the degree of reliance on their reports on such information should
be restricted in light of the limited nature of the review procedures applied.
PricewaterhouseCoopers LLP is not subject to the liability provisions of Section
11 of the Securities Act of 1933, as amended (the Act), for their reports on the
unaudited interim consolidated financial information because such reports are
not "reports" or a "part" of the Registration Statement prepared or certified by
PricewaterhouseCoopers LLP within the meaning of Sections 7 and 11 of the Act.

  With respect to the unaudited interim consolidated financial information of
COM/Energy for the periods ended March 31, 1999 and 1998, incorporated by
reference in this Prospectus, Arthur Andersen LLP has reported that they have
applied limited procedures in accordance with professional standards for a
review of such information.  However, their separate reports included
COM/Energy's Quarterly Reports on Form 10-Q for the quarter ended March 31,
1999, and incorporated by reference herein, state that they did not audit and
they do not express an opinion on that interim consolidated financial
information.  Accordingly, the degree of reliance on their reports on such
information should be restricted in light of the limited nature of the review
procedures applied.  Arthur Andersen LLP is not subject to the liability
provisions of Section 11 of the Securities Act of 1933, as amended (the Act),
for their reports on the unaudited interim consolidated financial information
because such reports are not "reports" or a "part" of the Registration Statement
prepared or certified by Arthur Andersen LLP within the meaning of Sections 7
and 11 of the Act.

  Ropes & Gray has reviewed the statements as to matters of law and legal
conclusions under the caption "Description of Shares" herein.  Such statements
are included on the authority of such firm.

  You should rely only on the information contained or incorporated by reference
in this Prospectus and in any accompanying prospectus supplement.  No one has
been authorized to provide you with different information.

                                      15


  The Common Shares offered by this Prospectus are not being offered in any
jurisdiction where the offer is not permitted.

  You should not assume that the information in this Prospectus or any
prospectus supplement is accurate as of any date other than the date on the
front of the documents.


                                                     DIVIDEND REINVESTMENT AND

   TABLE OF CONTENTS
                                                     COMMON SHARES PURCHASE PLAN
Available Information                           2
Incorporation of Certain Documents
 by Reference                                   2
The Company                                     3
Description of the Plan                         3
 Purpose                                        3
 Features and Benefits                          3
 Administration                                 4            PROSPECTUS
 Participation                                  4
 Participation by Shareholders                  4
 Participation by Customers and Employees       5
 Optional Cash Payments                         6
 Payroll Deductions for Employees               7
 Dividend Reinvestment                          7
 Purchases                                      8
 Costs                                          9
 Reports to Participants                        9
 Dividends                                      9
 Certificates for Shares                        9
 Changing Method of Participation
  and Withdrawal                               10
 Other Information                             11
Use of Proceeds                                13
Description of Shares                          13
Legal Opinions                                 15
Experts                                        15

                                      16


                                    PART II

                            INFORMATION REQUIRED IN
                           THE REGISTRATION STATEMENT

Item 14.  Other Expenses of Issuance and Distribution

  The following table sets forth the costs and expenses payable by NSTAR in
connection with the sale of common shares being registered. All amounts are
estimates except the SEC registration fee.

      SEC Registration fee              $   N/A
      Legal fees and expenses             5,000
      Accounting fees and expenses        1,000
      Printing Fees                       1,000
      Transfer Agent Fees                   N/A
      Miscellaneous                       1,000

      Total                              $8,000

Item 15.  Indemnification of Trustees and Officers.

  NSTAR's Declaration of Trust (the "Declaration of Trust") provides that, to
the extent legally permissible, each of NSTAR's Trustees and officers shall be
indemnified by NSTAR's trust estate against any loss, liability or expense,
including amounts paid in satisfaction of judgments, in compromise or as fines
and penalties, and counsel fees, imposed upon or reasonably incurred by such
person in connection with the defense or disposition of any action, suit or
other proceeding, whether civil or criminal, in which such person may be
involved or with which such person may be threatened, while in office or
thereafter, by reason of such person's being or having been such a Trustee or
officer, except with respect to any matter as to which such person shall have
been adjudicated in such action, suit or proceeding not to have acted in good
faith in the reasonable belief that his or her action was in the best interests
of NSTAR; provided, however, that as to any matter disposed of by a compromise
payment by such Trustee or officer, pursuant to a consent decree or otherwise,
no indemnification either for said payment or for any other expenses shall be
provided unless such compromise shall be approved as in the best interests of
NSTAR, after notice that it involves such indemnification, (i) by a
disinterested majority of the Trustees then in office, or (ii) by a majority of
the disinterested Trustees then in office, provided that there has been obtained
an opinion in writing of independent legal counsel to the effect that such
Trustee or officer appears to have acted in good faith in the reasonable belief
that his or her action was in the best interests of NSTAR, or (iii) by the vote,
at a meeting duly called and held, of the holders of a majority of the shares
outstanding and entitled to vote thereon, exclusive of any shares owned by any
interested Trustee or officer.


  In discharging his or her duties, a Trustee or officer of NSTAR, when acting
in good faith, shall be fully protected in relying upon the books of account of
NSTAR or of another organization in which he or she serves as contemplated by
the indemnification provisions of the Declaration of Trust, reports made to
NSTAR or to such other organization by any of its officers or employees or by
counsel, accountants, appraisers or other experts or consultants selected with
reasonable care by the Trustees or similar governing body of such other
organization, or upon other records of NSTAR or of such other organization.  The
rights of indemnification provided in the Declaration of Trust shall not be
exclusive of or affect any other rights to which any Trustee or officer may be
entitled and such rights shall inure to the benefit of his or her successors,
heirs, executors, administrators and other legal representatives.  As used in
this provision, the terms "Trustee" and "officer" include persons who serve at
the request of NSTAR as directors, officers, or trustees of another organization
in which NSTAR has any direct or indirect interest as a shareholder, creditor or
otherwise.

  Expenses, including counsel fees, reasonably incurred by any Trustee or
officer with respect to the defense or disposition of any action, suit or
proceeding referred to in the indemnification provisions of the Declaration of
Trust may be advanced by NSTAR prior to the final disposition of such action,
suit or proceeding, upon receipt of an undertaking by or on behalf of the
recipient to repay such amount unless it is ultimately determined that he or she
is entitled to indemnification.  Nothing contained in these provisions affects
any rights to indemnification to which NSTAR personnel other than Trustees and
officers may be entitled by contract or otherwise under law.  No Trustee shall
be obligated to give any bond or other security for the performance of any of
his or her duties.

Item 16.  Exhibits.

Exhibit Number    Description of Exhibit

4.1               NSTAR Declaration of Trust, dated April 20, 1999 (incorporated
                  by reference to Annex D to the Proxy Statement/Prospectus in
                  Part I of Registration Statement on Form S-4 of NSTAR (No.
                  333-78285)).

4.2               By-laws of NSTAR, dated April 20, 1999 (incorporated by
                  reference to Annex E to the Proxy Statement/Prospectus in Part
                  I of Registration Statement on Form S-4 of NSTAR (No. 333-
                  78285)).

5.1               Opinion of Ropes & Gray.

15.1              PricewaterhouseCoopers LLP's Letter Re Unaudited Interim
                  Financial Information.

23.1              Consent of PricewaterhouseCoopers LLP.


23.2              Consent of Arthur Andersen LLP.

23.3              Consent of Ropes & Gray (included in Opinion filed as Exhibit
                  5.1).

24                Power of Attorney.



Item 17.   Undertakings.

  (a) The Registrant hereby undertakes:

      (1)  to file, during any period in which offers or sales are being made, a
  post-effective amendment to this registration statement;

          (i) to include any prospectus required by Section 10(a)(3) of the
          Securities Act of 1933 (the "Securities Act");

          (ii) to reflect in the prospectus any facts or events arising after
          the effective date of the registration statement (or the most recent
          post-effective amendment thereof), which, individually or in the
          aggregate, represent a fundamental change in the information set forth
          in the registration statement; and

          (iii) to include any material information with respect to the plan of
          distribution not previously disclosed in the registration statement or
          any material change to such information in the registration statement;

  provided, however, that paragraphs (a)(l)(i) and (ii) shall not apply if the
  information required to be included in a post-effective amendment by those
  paragraphs is contained in periodic reports filed by the registrant pursuant
  to Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (the
  "Exchange Act") that are incorporated by reference in the registration
  statement;

      (2)  that, for the purpose of determining any liability under the
  Securities Act, each such post-effective amendment shall be deemed to be a new
  registration statement relating to the securities offered herein, and the
  offering of such securities at that time shall be deemed to be the initial
  bona fide offering thereof; and

      (3)  to remove from registration by means of a post-effective amendment
  any of the securities being registered which remain unsold at the termination
  of the offering.


  (b) The Registrant hereby undertakes that, for purposes of determining any
liability under the Securities Act, each filing of the Registrant's annual
report pursuant to Section 13(a) or 15(d) of the Exchange Act (and, where
applicable, each filing of an employee benefit plan's annual report pursuant to
Section 15(d) of the Exchange Act) that is incorporated by reference in the
registration statement shall be deemed to be a new registration statement
relating to the securities offered therein, and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.

  (c) Insofar as indemnification for liabilities arising under the Securities
Act may be permitted to trustees, officers and controlling persons of the
Registrant pursuant to the foregoing provisions, or otherwise, the Registrant
has been advised that in the opinion of the Securities and Exchange Commission
such indemnification is against public policy as expressed in the Securities Act
and is, therefore, unenforceable.  In the event that a claim for indemnification
against such liabilities (other than the payment by the Registrant of expenses
incurred or paid by a trustee, officer or controlling person of the Registrant
in the successful defense of any action, suit or proceeding) is asserted by such
trustee, officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Securities Act and will be governed by the final
adjudication of such issue.


                                   SIGNATURES

  Pursuant to the requirements of the Securities Act of 1933, the registrant has
duly caused this Post-Effective Amendment No. 1 on Form S-3 to the Form S-4
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Boston, Commonwealth of Massachusetts, on the
18th of August 1999.

                  NSTAR

              BY:     /s/ Thomas J. May
                      ---------------------------------
              TITLE:  Chairman of the Board, Chief Executive Officer,
                      Treasurer and Trustee

  Pursuant to the requirements of the Securities Act of 1933, as amended, this
Post-Effective Amendment No. 1 on Form S-3 to the Form S-4 Registration
Statement has been signed below by the following persons in the capacities
stated below on the 18th of August 1999.


/s/ Thomas J. May         Chairman of the Board,
- -----------------         Chief Executive Officer,
THOMAS J. MAY             Treasurer, and Trustee



/s/ Russell D. Wright     President, Chief Operating Officer,
- ---------------------     Clerk, and Trustee
RUSSELL D. WRIGHT