Execution Copy

                           KMC TELECOM HOLDINGS, INC.

                           CERTIFICATE OF THE POWERS,
                   DESIGNATIONS, PREFERENCES AND RIGHTS OF THE
                SERIES D CUMULATIVE CONVERTIBLE PREFERRED STOCK,
                            PAR VALUE $.0l PER SHARE

                     Pursuant to Sections 141 and 151 of the
                General Corporation Law of the State of Delaware

          As contemplated  by Section 141 of the General  Corporation Law of the
State of Delaware (the "DGCL"), the following resolution was duly adopted by the
Board of Directors of KMC Telecom  Holdings,  Inc., a Delaware  corporation (the
"Corporation"), by unanimous written consent, dated October 31, 1997:

          WHEREAS,  the Board of Directors  of the  Corporation  is  authorized,
within the  limitations  and  restrictions  stated in the Amended  and  Restated
Certificate of  Incorporation  of the  Corporation,  to provide by resolution or
resolutions  for the issuance of shares of preferred  stock,  par value $.01 per
share, of the Corporation,  in one or more series with such voting powers,  full
or limited,  or without voting powers,  and such  designations,  preferences and
relative,  participating,  optional or other special rights, and qualifications,
limitations or  restrictions  as shall be stated and expressed in the resolution
or  resolutions  providing  for the  issuance  thereof  adopted  by the Board of
Directors,   and  as  are  not  stated  and  expressed  in  the  Certificate  of
Incorporation,  or any amendment  thereto,  including (but without  limiting the
generality  of the  foregoing)  such  provisions  as may be  desired  concerning
voting,  redemption,  dividends,  dissolution or the  distribution of assets and
such other  subjects or matters as may be fixed by resolution or  resolutions of
the Board of Directors under the DGCL;

          WHEREAS,  the Board of Directors of the  Corporation,  pursuant to its
authority under Section 151 of the DGCL,  desires to authorize and fix the terms
of its Series D Cumulative Convertible Preferred Stock; and

          WHEREAS, the Board of Directors of the Corporation has determined that
such Series D Cumulative  Convertible  Preferred Stock shall constitute  "Parity
Preferred  Stock"  within  the  meaning  of  the  Certificates  of  the  Powers,
Designations,  Preferences and Rights of the  Corporation's  Series A Cumulative
Convertible Preferred Stock, Series B Cumulative Convertible Preferred Stock and
Series C Preferred Stock;

          NOW, THEREFORE, BE IT RESOLVED:

          1. DESIGNATION AND NUMBER OF SHARES. There shall be hereby established
a series of  preferred  stock  designated  as "Series D  Cumulative  Convertible
Preferred  Stock" (such Series  being  hereinafter  referred to as the "Series D
Preferred  Stock").  The authorized number of shares of Series D Preferred Stock
shall be 25,000.  The  liquidation  preference  of the Series D Preferred  Stock
shall be $100 per share (the "Liquidation Preference").





          2. RANK. The Series D Preferred Stock shall,  with respect to dividend
distributions  and  distributions  of assets  and rights  upon the  liquidation,
winding-up and dissolution of the Corporation,  rank senior to the Common Stock,
par value $.0l per share,  of the  Corporation  (the "Common Stock") and to each
other class or series of Capital Stock of the Corporation (other than the Parity
Preferred  Stock)  hereafter  created  (the Common Stock and such other class or
series of Capital Stock of the Corporation other than Parity Preferred Stock are
hereinafter collectively referred to as the "Junior Stock").

          3. DIVIDENDS.

          (a) Beginning on the date of issuance of the Series D Preferred Stock,
the  holders of the  outstanding  shares of Series D  Preferred  Stock  shall be
entitled to receive,  when,  as and if declared by the Board of Directors of the
Corporation,  out of funds legally  available  therefor,  cash dividends on each
share  of  Series  D  Preferred  Stock at an  annual  rate  equal to 7.0% of the
Liquidation Preference,  payable quarterly in arrears on the applicable Dividend
Payment Date or the next  succeeding  Business Day, if the  applicable  Dividend
Payment Date is not a Business Day.  Notwithstanding the foregoing, the dividend
payable on each share of Series D  Preferred  Stock with  respect to the Initial
Dividend  Period  shall  be  equal  to (i)  7.0% of the  Liquidation  Preference
multiplied  by (ii) a  fraction  equal  to (A) the  number  of  days  from  (and
including)  the  Series D  Preferred  Stock  Issue Date to (but  excluding)  the
Dividend Payment Date with respect to the Initial Dividend Period divided by (B)
365. All dividends shall be cumulative,  whether or not earned or declared, from
the date of  issuance  of the  Series D  Preferred  Stock and  shall be  payable
quarterly in arrears on each  Dividend  Payment  Date,  commencing  on the first
Dividend  Payment  Date after the date of  issuance  of the  Series D  Preferred
Stock. If any dividend (or portion thereof) payable on any Dividend Payment Date
is not declared or paid in full on such  Dividend  Payment  Date,  the amount of
such dividend  payable that is not paid on such date shall  increase at the rate
of 7.0% per annum  (compounded  quarterly on each  subsequent  Dividend  Payment
Date) from such Dividend  Payment Date until paid in full. Each  distribution on
the  Series D  Preferred  Stock  shall be  payable  to holders of record as they
appear on the stock books of the Corporation on such record dates, not less than
ten (10) nor more than sixty (60) days  preceding the related  Dividend  Payment
Date, as shall be fixed by the Board of Directors of the Corporation.

          (b) All  accumulated  and unpaid  dividends  on the Series D Preferred
Stock shall be paid by the  Corporation  upon the  occurrence  of a  Realization
Event,  without  reference to any regular  Dividend  Payment Date, to holders of
record on such date. The Corporation shall send by first class,  postage prepaid
mail a notice of the  Realization  Event to all  holders  of Series D  Preferred
Stock that are entitled to receive such dividends.  In the case of a Realization
Event which is an initial  public  offering,  if any such holder  gives  written
notice to the  Corporation  that such holder wishes to receive such  accumulated
unpaid  dividends  in the form of shares of  Common  Stock in lieu of cash,  the
Corporation,  in lieu of a cash  payment,  shall  issue to such  holder  on such
Dividend  Payment Date, a number of shares of Common Stock equal to the quotient
obtained by dividing (x) the aggregate  accumulated and unpaid  dividends on the
shares of Series D Preferred Stock held by such holder by (y) the price at which
shares  of  Common  Stock  are  sold  in  such  offering  (before  deduction  of
underwriting discounts and expenses of sale).

          (c) All  dividends  paid with  respect to shares of Series D Preferred
Stock  pursuant to Section 3(a) shall be paid pro rata and in like manner to all
of the holders entitled thereto.


                                       2



          (d) Except as  otherwise  provided  in  paragraph  (b) above,  nothing
herein  contained  shall in any way or under any  circumstances  be construed or
deemed to require the Board of Directors of the  Corporation to declare,  or the
Corporation  to pay or set apart for  payment,  any  dividends  on shares of the
Series D Preferred Stock at any time.

          (e)  Whenever  the  provisions  hereof  require  that  the  amount  of
dividends  with respect to the Series D Preferred  Stock be determined  for less
than a full  quarterly  period ending on a Dividend  Payment Date, the amount of
dividends for such period shall be equal to 7.0% of the  Liquidation  Preference
multiplied  by a fraction  equal to (i) the number of days from (and  including)
the most recent  Dividend  Payment Date to (but  excluding)  the last day of the
period in respect of which such determination is being made divided by (ii) 365.

          4. LIQUIDATION PREFERENCE.

          (a)  In  the  event  of  any  voluntary  or  involuntary  liquidation,
dissolution  or  winding-up  of the affairs of the  Corporation,  the holders of
shares of Parity  Preferred Stock  (including the Series D Preferred Stock) then
outstanding shall be entitled to be paid for each share held thereby, out of the
assets of the Corporation  available for  distribution to its  stockholders,  an
amount in cash equal to the Liquidation  Preference plus an amount in cash equal
to  all  accumulated  and  unpaid  dividends  thereon  (calculated  pursuant  to
Paragraph  3(a)) to the date fixed for  liquidation,  dissolution  or winding-up
(including  an amount equal to a prorated  dividend for the period from the last
Dividend  Payment  Date  to the  date  fixed  for  liquidation,  dissolution  or
winding-up),  before any payment shall be made or any assets  distributed to the
holders of any  shares of Junior  Stock.  Except as  provided  in the  preceding
sentence,  holders  of the  Parity  Preferred  Stock  (including  the  Series  D
Preferred  Stock) shall not be entitled to any  distribution in the event of any
liquidation, dissolution or winding-up of the affairs of the Corporation. If the
assets  of the  Corporation  are not  sufficient  to pay in full  the  foregoing
liquidation  payments payable to the holders of outstanding shares of the Parity
Preferred Stock  (including the Series D Preferred  Stock),  then the holders of
all shares of Parity  Preferred Stock  (including the Series D Preferred  Stock)
shall share ratably in such distribution of assets in accordance with the amount
that would be payable on such  distribution  if the amounts to which the holders
of  outstanding  shares  of  Parity  Preferred  Stock  (including  the  Series D
Preferred  Stock)  are  entitled  were  paid in  full.  If all of the  foregoing
liquidation  payments with respect to any share of Series D Preferred Stock have
been made, such share may not be converted into Common Stock pursuant to Section
5.

          (b) For the purposes of this Section 4,  neither the  voluntary  sale,
conveyance,  exchange or transfer  (for cash,  shares of stocks,  securities  or
other  consideration)  of all or  substantially  all or part of the  property or
assets of the  Corporation  nor the  consolidation  or merger of the Corporation
with  one or more  other  corporations  shall  be  deemed  to be a  liquidation,
dissolution  or  winding-up,  voluntary  or  involuntary,  of the affairs of the
Corporation (unless such sale, conveyance, exchange or transfer is in connection
with  a   liquidation,   dissolution   or  winding-up  of  the  affairs  of  the
Corporation).

          4A. CONVERSION INTO SERIES C PREFERRED STOCK

          At any time  prior to a  Qualified  Public  Offering,  each  holder of
Series D Preferred  Stock shall have the right to convert all, but not less than
all, of such  holder's  shares of Series D Preferred  Stock  (together  with all
accumulated  unpaid  dividends  thereon to the date of conversion) into an equal
number of shares of Series C  Preferred  Stock  (together  with all  accumulated
unpaid dividends thereon to the date of conversion).  In order to convert shares
of Series D Preferred Stock pursuant to this Section 4A the holder thereof shall
surrender  at the office of the  Corporation  the  certificate  or  certificates
therefor,  duty endorsed to the Corporation in blank, and give written notice to
the  Corporation  that such holder elects to convert such shares and shall state
in writing  therein  the name or names  (with  addresses)  in which such  holder
wishes the certificate or certificates of Series C Preferred Stock to be issued.
Shares of Series D Preferred Stock shall be deemed to have been converted on the
date of surrender of such certificate or certificates as provided above, and the
person or persons  entitled to receive  the shares of Series C  Preferred  Stock
issuable  upon such  conversion  shall be treated for all purposes as the record
holder or  holders of such  Series C  Preferred  Stock on such date.  As soon as
practicable on or after such conversion  date, the  Corporation  shall issue and
deliver  a  certificate  or  certificates  for the  number of shares of Series C
Preferred Stock issuable upon conversion.


                                       3



          5. CONVERSION.

          (a)  CONVERSION  PRICE.  Shares  of  Series  D  Preferred  Stock to be
converted  into shares of Common  Stock shall be so  converted  at a  conversion
price  (which  price shall be adjusted to the nearest  fourth  decimal  place as
hereinafter  provided  and, as so adjusted,  is  hereinafter  referred to as the
"Conversion Price") equal to: (i) from the date of initial issuance of shares of
Series D Preferred  Stock to but  excluding  the  30-month  anniversary  of such
issuance,  $52.50  per  share of  Common  Stock,  with  each  share of  Series D
Preferred  Stock being valued at $100.00 for such  purpose;  PROVIDED,  HOWEVER,
that if a  Realization  Event  shall  occur  during  such  30-month  period  the
Conversion  Price shall equal to a fraction,  the  numerator of which is (A) the
consideration  per share of Common Stock (on a Fully Diluted basis)  received in
connection with such Realization Event, and the denominator of which is (B) 1.30
raised to a number equal to the number of years (or fraction  thereof)  from the
date of initial issuance of shares of Series D Preferred Stock until the date of
such Realization Event, but in no case shall be greater than $52.50 per share of
Common Stock nor less than $42.18 per share of Common  Stock;  and (ii) from and
after the thirty month  anniversary of the date of initial issuance of shares of
Series D Preferred  Stock (subject to paragraph (b) below),  $42.18 per share of
Common  Stock,  with each  share of Series D  Preferred  Stock  being  valued at
$100.00  for  such  purpose;  PROVIDED,  HOWEVER,  that in no  event  shall  the
Conversion Price be less than the par value, if any, of the Common Stock.

          (b) AUTOMATIC  CONVERSION  UPON A QUALIFIED  PUBLIC  OFFERING.  Upon a
Qualified  Public  Offering,  each  share of  Series  D  Preferred  Stock  shall
automatically  convert,  without  any action on the part of the holder  thereof,
into shares of Common Stock at the Conversion Price in effect at such time, plus
the right to receive an amount of cash equal to the accumulated unpaid dividends
on such share of Series D  Preferred  Stock to and  including  such date (or the
right to receive  additional  shares of Common  Stock in lieu of cash  dividends
pursuant to Section 3(b)).

          (c) CONVERSION AT THE OPTION OF THE HOLDER.  At any time and from time
to time prior to a Qualified Public Offering,  each holder of Series D Preferred
Stock shall have the right to convert such holder's shares of Series D Preferred
Stock, in whole or in part, into shares of Common Stock at the Conversion  Price
in effect at such time, plus the right to receive an amount of cash equal to the
accumulated  unpaid  dividends  on the  shares  of Series D  Preferred  Stock so
converted to and  including the  Conversion  Date (as defined  below);  provided
that, if such Conversion Date is prior to a Realization  Event,  the Corporation
may, in lieu of making a payment in cash equal to such amount,  deliver a number
of shares of Common Stock equal to such amount  divided by the Fair Market Value
of one share of Common Stock.  In order to convert  shares of Series D Preferred
Stock  pursuant to this Section 5(c) the holder  thereof shall  surrender at the
office  of the  Corporation  the  certificate  or  certificates  therefor,  duly
endorsed to the Corporation in blank, and give written notice to the Corporation
that such  holder  elects to  convert  such  shares  and shall  state in writing
therein  the name or names  (with  addresses)  in which such  holder  wishes the
certificate  or  certificates  of Common Stock to be issued.  Shares of Series D
Preferred  Stock shall be deemed to have been converted on the date of surrender
of such certificate or certificates as provided above (the  "Conversion  Date"),
and the  person or  persons  entitled  to  receive  the  shares of Common  Stock
issuable  upon such  conversion  shall be treated for all purposes as the record
holder or holders of such Common Stock on such date. As soon as  practicable  on
or after  the  Conversion  Date,  the  Corporation  shall  issue  and  deliver a
certificate  or  certificates  for the number of shares of Common Stock issuable
upon conversion.


                                       4



          (d) FRACTIONAL SHARES, PARTIAL CONVERSION.  No fractional shares shall
be issued  upon  conversion  of shares of Series D  Preferred  Stock into Common
Stock. In case the number of shares of Series D Preferred  Stock  represented by
the certificate or certificates  surrendered  pursuant to this Section 5 exceeds
the number of shares  converted,  the Corporation  shall,  upon such conversion,
execute  and deliver to the holder,  at the  expense of the  Corporation,  a new
certificate or certificates for the number of shares of Series D Preferred Stock
represented by the certificate or certificates  surrendered  which are not to be
converted.  If any  fractional  share of  Common  Stock  would,  except  for the
provisions of the first  sentence of this Section  5(d), be delivered  upon such
conversion, the Corporation,  in lieu of delivering such fractional share, shall
pay to the holder  surrendering  the Series D Preferred  Stock for conversion an
amount in cash equal to the current  market  price of such  fractional  share as
determined in good faith by the Board of Directors.

          (e)  ADJUSTMENT  OF  CONVERSION  PRICE UPON  ISSUANCE OF COMMON STOCK.
Except as  provided in Section  5(f),  if and  whenever  the  Corporation  shall
hereafter issue or sell, or is, in accordance  with  subsection  5(e)(1) through
5(e)(6),  deemed to have  issued  or sold,  any  shares  of  Common  Stock for a
consideration  per share less than the  Conversion  Price in effect  immediately
prior to the time of such  issue or sale,  then,  forthwith  upon such  issue or
sale, the Conversion  Price shall be reduced to the price determined by dividing
(i) an amount  equal to the sum of (a) the  number  of  shares  of Common  Stock
outstanding  immediately  prior  to such  issue or sale  (determined  on a Fully
Diluted  basis)  multiplied  by the then existing  Conversion  Price and (b) the
consideration,  if any,  received by the Corporation upon such issue or sale, by
(ii) the total number of shares of Common Stock  outstanding  immediately  after
such issue or sale (deter-mined on a Fully Diluted basis).

          For purposes of this Section 5(e), the following  subsections  5(e)(1)
to 5(e)(6) shall also be applicable:

          5(e)(1)  ISSUANCE OF RIGHTS OR OPTIONS.  In case at any time hereafter
the Corporation  shall in any manner grant (whether directly or by assumption in
a merger or otherwise) any Options to purchase  Common Stock or any  Convertible
Securities,  whether or not such Options or the right to convert or exchange any
such Convertible Securities are immediately exercisable, and the price per share
for which Common Stock is issuable upon the exercise of such Options or upon the
conversion or exchange of such  Convertible  Securities  (determined by dividing
(i) the total  amount,  if any,  received or receivable  by the  Corporation  as
consideration  for the  granting of such  Options,  plus the  minimum  aggregate
amount of additional  consideration payable to the Corporation upon the exercise
of all  such  Options,  plus,  in the  case  of such  Options  which  relate  to
Convertible   Securities,   the   minimum   aggregate   amount   of   additional
consideration,  if any,  payable  upon  the  issue  or sale of such  Convertible
Securities  and upon the  conversion  or  exchange  thereof,  by (ii) the  total
maximum  number of shares of Common  Stock  issuable  upon the  exercise of such
Options or upon the  conversion or exchange of all such  Convertible  Securities
issuable  upon the exercise of such Options)  shall be less than the  Conversion
Price in effect  immediately  prior to the time of the granting of such Options,
then the total  maximum  number of shares  of  Common  Stock  issuable  upon the
exercise of such  Options or upon  conversion  or exchange of the total  maximum
amount of such Convertible Securities issuable upon the exercise of such Options
shall be deemed to have been  issued  for such price per share as of the date of
granting of such  Options or the  issuance of such  Convertible  Securities  and
thereafter  shall be deemed to be outstanding.  Except as otherwise  provided in
subsection 5(e)(3), no adjustment of the Conversion Price shall be made upon the
actual  issue  of such  Common  Stock  or of such  Convertible  Securities  upon
exercise  of such  Options or upon the actual  issue of such  Common  Stock upon
conversion or exchange of such Convertible Securities.


                                       5



          5(e)(2)  ISSUANCE OF CONVERTIBLE  SECURITIES.  In case the Corporation
shall  hereafter in any manner issue  (whether  directly or by  assumption  in a
merger or  otherwise)  or sell any  Convertible  Securities,  whether or not the
rights to exchange or convert any such  Convertible  Securities are  immediately
exercisable,  and the price per share for which  Common  Stock is issuable  upon
such  conversion  or  exchange  (determined  by  dividing  (i) the total  amount
received or receivable by the Corporation as consideration for the issue or sale
of such Convertible Securities,  plus the minimum aggregate amount of additional
consideration,  if any,  payable  to the  Corporation  upon  the  conversion  or
exchange  thereof,  by (ii) the total  maximum  number of shares of Common Stock
issuable  upon the  conversion or exchange of all such  Convertible  Securities)
shall be less than the Conversion Price in effect  immediately prior to the time
of such issue or sale,  then the total maximum  number of shares of Common Stock
issuable upon conversion or exchange of all such Convertible Securities shall be
deemed to have been  issued for such price per share as of the date of the issue
or sale of such  Convertible  Securities  and  thereafter  shall be deemed to be
outstanding,  provided  that (a) except as  otherwise  provided in  subparagraph
5(e)(3),  no  adjustment of the  Conversion  Price shall be made upon the actual
issue of such Common  Stock upon  conversion  or  exchange  of such  Convertible
Securities and (b) if any such issue or sale of such  Convertible  Securities is
made upon  exercise of any Options to purchase any such  Convertible  Securities
for  which  adjustments  of the  Conversion  Price  have  been or are to be made
pursuant to other provisions of this Section 5(e), no further  adjustment of the
Conversion Price shall be made by reason of such issue or sale.

          5(e)(3) CHANGE IN OPTION PRICE OR CONVERSION  RATE. Upon the happening
of any of the following  events,  namely,  if the purchase price provided for in
any Option referred to in subsection 5(e)(1), the additional  consideration,  if
any,  payable  upon the  conversion  or exchange of any  Convertible  Securities
referred to in  subsection  5(e)(1) or 5(e)(2) or the rate at which  Convertible
Securities  referred to in subsection 5(e)(1) or 5(e)(2) are convertible into or
exchangeable  for Common  Stock  shall  change at any time  (including,  but not
limited to, changes under or by reason of provisions designed to protect against
dilution),  the  Conversion  Price in  effect  at the time of such  event  shall
forthwith be readjusted to the Conversion  Price which would have been in effect
at such  time had such  Options  or  Convertible  Securities  still  outstanding
provided for such changed purchase price, additional consideration or conversion
rate, as the case may be, at the time  initially  granted,  issued or sold,  but
only if as a result  of such  adjustment  the  Conversion  Price  then in effect
hereunder is thereby  reduced;  and on the termination of any such Option or any
such right to convert or exchange such  Convertible  Securities,  the Conversion
Price then in effect  hereunder  shall  forthwith be increased to the Conversion
Price which would have been in effect at the time of such  termination  had such
Option or Convertible Securities, to the extent outstanding immediately prior to
such termination, never been issued.

          5(e)(4)  CONSIDERATION  FOR STOCK. In case any shares of Common Stock,
Options  or  Convertible  Securities  shall  be  issued  or sold for  cash,  the
consideration received therefor shall be deemed to be the amount received by the
Corporation  therefor,  without deduction  therefrom of any expenses incurred or
any  underwriting  commissions or concessions paid or allowed by the Corporation
in  connection  therewith.  In case any  shares  of  Common  Stock,  Options  or
Convertible  Securities  shall be issued or sold for a consideration  other than
cash,  the  amount  of  the  consideration  other  than  cash  received  by  the
Corporation  shall be  deemed  to be the fair  value  of such  consideration  as
determined  in good faith by the Board of  Directors,  without  deduction of any
expenses incurred or any underwriting commissions or concessions paid or allowed
by the Corporation in connection therewith.  In case any Options shall be issued
in connection  with the issue and sale of other  securities of the  Corporation,
together comprising one integral transaction in which no specific  consideration
is  allocated  to such Options by the parties  thereto,  such  Options  shall be
deemed to have been issued for such consideration as determined in good faith by
the Board of Directors of the Corporation.

          5(e)(5)  RECORD DATE. In case the  Corporation  shall take a record of
the holders of its Common Stock for the purpose of entitling them (i) to receive
a dividend or other distribution payable in Common Stock, Options or Convertible
Securities  or (ii) to  subscribe  for or  purchase  Common  Stock,  options  or
Convertible Securities,  then such record date shall be deemed to be the date of
the issue or sale of the shares of Common  Stock  deemed to have been  issued or
sold  upon  the  declaration  of such  dividend  or the  making  of  such  other
distribution  or the  date of the  granting  of such  right of  subscription  or
purchase, as the case may be.


                                       6



          5(e)(6)  TREASURY  SHARES.  The  number  of  shares  of  Common  Stock
outstanding  at any given time shall not include  shares owned or held by or for
the account of the Corporation,  and the disposition of any such shares shall be
considered  an issue or sale of Common  Stock for the  purpose  of this  Section
5(e).

          (f) EXCEPTIONS TO CONVERSION  PRICE  ADJUSTMENT.  Notwithstanding  the
foregoing,  no adjustment to the Conversion Price shall be made pursuant to this
Section 5 in  connection  with the  grant,  issuance  or sale of  Common  Stock,
Convertible  Securities,  warrants,  options or other fights to subscribe for or
purchase Common Stock or Convertible Securities:  (i) pursuant to employee stock
purchase  or  stock  option  ownership  plans  adopted  by the  Corporation  for
employees,  consultants  and/or directors of the Corporation and its affiliates;
(ii) pursuant to the terms of any Convertible Securities,  warrants,  options or
other rights to subscribe  for or purchase  granted,  issued or sold pursuant to
clause (ii) above; (iii) pursuant to the High Yield Debt and Equity Offering (as
defined in a Subordinated Loan and Security Agreement, dated as of September 22,
1997,  among  KMC  Telecom  Inc.  ("KMC")  and KMC  Telecom  II,  Inc.  and AT&T
Commercial  Finance  Corporation,  as in effect on the Series C Preferred  Stock
Issue Date) or a subsequent debt offering  occurring prior to December 31, 1998;
(iv) pursuant to the terms of any Convertible Securities,  warrants,  options or
other rights to subscribe  for or purchase  granted,  issued or sold pursuant to
clauses (iii) above;  or (v) pursuant to Section 10C of the Amended and Restated
Note  Purchase  and  Investment  Agreement,  dated as of October  22,  1996,  as
amended,  by and  among the  Corporation,  Nassau  Capital  Partners  L.P.,  NAS
Partners I L.L.C.  and Harold N. Kamine;  PROVIDED that the aggregate  number of
shares of Common Stock issued or issuable pursuant to clauses (i) and (ii) above
shall not exceed 15% of the Common Stock (on a Fully Diluted basis)  outstanding
from time to time and the  aggregate  number of shares of Common Stock issued or
issuable  pursuant  to clause  (iii) and (iv) above  shall not exceed 11% of the
Common  Stock (on a Fully  Diluted  basis)  outstanding  from time to time;  and
FURTHER  PROVIDED that for the purposes of this Section 5(f): (a) 221,500 shares
of Common  Stock  initially  allocated  under the 1997 Stock Option Plan will be
deemed  outstanding  regardless  of the number of shares  actually  granted  and
exercisable  thereunder  and (b) shares of Common Stock issued or issuable  upon
exercise of options not among the 221,500 shares initially allocated pursuant to
the 1997 Stock Option Plan and which, when issued, were subject to clause (i) or
(ii) above,  will not be deemed  outstanding,  regardless of whether or not they
have been granted or are  exercisable.  (g) SUBDIVISION OR COMBINATION OF COMMON
STOCK. In case the Corporation  shall at any time subdivide (by any stock split,
stock  dividend or  otherwise)  its  outstanding  shares of Common  Stock into a
greater number of shares,  the Conversion Price in effect  immediately  prior to
such subdivision shall be proportionately reduced, and, conversely,  in case the
outstanding  shares of Common Stock shall be combined  into a smaller  number of
shares,  the Conversion  Price in effect  immediately  prior to such combination
shall be proportionately increased.

          (h) REORGANIZATION OR RECLASSIFICATION.  If any capital reorganization
or reclassification of the capital stock of the Corporation shall be effected in
such a way that  holders of Common  Stock shall be  entitled  to receive  stock,
securities or assets with respect to or in exchange for Common Stock, then, as a
condition of such reorganization or reclassification (but subject to Section 7),
lawful and adequate  provisions  shall be made whereby each holder of a share or
shares of Series D Preferred  Stock shall  thereupon  have the right to receive,
upon the basis and upon the terms and conditions specified herein and in lieu of
the  shares  of  Common  Stock  immediately   theretofore  receivable  upon  the


                                       7



conversion of such share or shares of Series D Preferred  Stock,  such shares of
stock,  securities  or assets as may be issued or payable  with respect to or in
exchange  for a number of  outstanding  shares of such Common Stock equal to the
number of shares of such Common Stock  immediately  theretofore  receivable upon
such conversion had such reorganization or reclassification not taken place, and
in any such case appropriate provisions shall be made with respect to the rights
and interests of such holder to the end that the provisions  hereof  (including,
without  limitation,  provisions for adjustments of the Conversion  Price) shall
thereafter  be  applicable,  as nearly as may be, in  relation  to any shares of
stock,  securities or assets  thereafter  deliverable  upon the exercise of such
conversion rights.

          (i) CARRYOVER. Notwithstanding any other provisions of this Section 5,
the  Corporation  shall not be required to make any adjustment to the Conversion
Price unless such  adjustment  would require an increase or decrease of at least
one percent (1%) in the Conversion Price. Any lesser adjustment shall be carried
forward and shall be made no later than the time of, and together with, the next
subsequent  adjustment  which,  together with any  adjustment or  adjustments so
carried forward, shall amount to an increase or decrease of at least one percent
(1%) in the Conversion Price.

          (j)  OTHER  EVENTS.   If  the  Corporation  shall  make  any  dividend
(excluding  cash dividends  payable out of accumulated  earnings and profits) or
distribution on the Common Stock or issue any Common Stock,  other capital stock
or other  security of the  Corporation  or any rights or warrants to purchase or
acquire any such security, which transaction does not result in an adjustment to
the Conversion Price pursuant to the foregoing provisions of this Section 5, the
Board of Directors may consider  whether such action is of such a nature that an
adjustment to the Conversion  Price should  equitably be made in respect of such
transaction.  If the Board of Directors of the  Corporation  determines  that an
adjustment to the Conversion  Price should be made, an adjustment  shall be made
effective  as of such  date,  as  determined  by the Board of  Directors  of the
Corporation.  The  determination of the Board of Directors of the Corporation as
to whether such an adjustment to the  Conversion  Price should be made,  and, if
so, as to what adjustment should be made and when, shall be final and binding on
the Corporation and all stockholders of the Corporation.  The Corporation  shall
be entitled to make such  additional  adjustments  in the Conversion  Price,  in
addition to those  required by the  foregoing  provisions  of this Section 5, as
shall be  necessary  in order that any  dividend  or  distribution  in shares of
capital stock of the Corporation,  subdivision,  reclassification or combination
of shares of stock of the Corporation or any recapitalization of the Corporation
shall not be taxable to the holders of the Common Stock.

          (k) NOTICE OF ADJUSTMENT. Upon any adjustment of the Conversion Price,
then and in each such case the Corporation shall give written notice thereof, by
delivery in person,  certified or registered mail, return receipt requested,  or
facsimile  addressed  to each  holder  of shares  of  Series D  Preferred  Stock
affected by such  adjustment at the address of such holder as shown on the books
of the Corporation, which notice shall state the Conversion Price resulting from
such adjustment,  setting forth in reasonable  detail the method upon which such
calculation is based.

          6. VOTING RIGHTS.

          (a) The  holders  of Series D  Preferred  Stock,  except as  otherwise
required  under  Delaware law or as set forth below in this Section 6, shall not
be entitled or permitted to vote on any matter required or permitted to be voted
upon by the stockholders of the Corporation.


                                       8



          (b) Subject to Section 7, without the prior  consent of the holders of
two-thirds  of the shares of the  Series D  Preferred  Stock  then  outstanding,
voting as a separate class, the Corporation shall not:

          (i)  increase  the  number  of  shares  of  Series D  Preferred  Stock
     authorized for issuance;

          (ii) merge or consolidate  with or into any other  company,  person or
     entity,  unless  holders of each share of Series D Preferred  Stock receive
     consideration in an amount equal to at least the greater of (A) the product
     of (x) the number of shares of Common Stock into which such share of Series
     D  Preferred  Stock is then  convertible  and (y) the  consideration  to be
     received by holders of each share of Common  Stock  pursuant to such merger
     or consolidation and (B) the Liquidation Preference of such share of Series
     D  Preferred  Stock  plus all  accumulated  but  unpaid  dividends  thereon
     (whether or not declared);

          (iii) amend, modify or repeal the powers,  preferences or rights of or
     the  restrictions  provided  for the  benefit  of  holders  of the Series D
     Preferred  Stock or the Common Stock if such action would affect the Series
     D Preferred Stock or the Common Stock adversely;

          (c) Without  the  consent of each  holder of Series D Preferred  Stock
affected thereby, the Corporation shall not reduce the Liquidation Preference of
the Series D Preferred Stock or the rate at which dividends  accumulate thereon,
or modify the dividend cumulation  provisions of the Series D Preferred Stock or
the times and prices at which the Series D Preferred  Stock may be redeemed in a
manner that would be adverse to the holders of Series D Preferred Stock.

          7.  OPTIONAL  REDEMPTION.  (a) The  outstanding  shares  of  Series  D
Preferred Stock shall be subject to redemption,  as hereinafter provided, at the
option of the  Corporation,  in whole  but not in part,  in  connection  with an
Acquisition  Event.  For  purposes  hereof,  "Acquisition  Event" shall mean any
merger or  consolidation  of the Corporation  with any other company,  person or
entity  (whether  or  not  the  Corporation  is the  entity  surviving  in  such
transaction)  as a result  of which  the  holders  of  shares  of  Common  Stock
(determined  on a fully  diluted  basis)  will hold less than a majority  of the
outstanding  shares of common  stock or other  equity  interests of the company,
person or entity resulting from such transaction (or any parent of such entity).

          (b) For each share of Series D Preferred  Stock  redeemed  pursuant to
this  Section 7, the  Corporation  shall be obligated on the date fixed for such
redemption  (the  "Redemption  Date"),  which date shall not be earlier than the
date of consummation of the applicable  Acquisition  Event, to pay to the holder
thereof (upon surrender by such holder at the Corporation's  principal office of
the certificate representing such share duly endorsed in blank or accompanied by
an appropriate form of assignment) an amount (the  "Redemption  Price") equal to
the greater of (A) the product of (x) the number of shares of Common  Stock into
which such share of Series D  Preferred  Stock is then  convertible  and (y) the
consideration  to be received by holders of each share of Common Stock  pursuant
to such  Acquisition  Event and (B) the Liquidation  Preference of such share of
Series D  Preferred  Stock plus all  accumulated  but unpaid  dividends  thereon
(whether or not declared).

          (c) Notice of any redemption of the Series D Preferred  Stock pursuant
to this Section 7 (specifying  the time and place of redemption,  the Redemption
Price,  the Conversion  Price and the date on and after which shares of Series D
Preferred  Stock may no longer be  converted)  shall be mailed by  certified  or
registered mail, return receipt requested,  to each holder of Series D Preferred
Stock,  at the address of such holder shown on the  Corporation's  records,  not
less than 30 nor more than 45 days prior to the Redemption Date.



                                       9



          (d) If the  Corporation  holds and sets aside money  sufficient to pay
the Redemption  Price of the Series D Preferred  Stock on the  Redemption  Date,
then on and after the  Redemption  Date:  (i) the  shares of Series D  Preferred
Stock  shall no longer be  convertible  into  shares of Common  Stock;  (ii) the
shares of Series D Preferred Stock will cease to be outstanding and dividends on
the Series D Preferred Stock will cease to be declared and paid,  whether or not
certificates  representing  the Series D Preferred  Stock have been delivered to
the  Corporation;  and (iii) all other  rights of the holder in respect  thereof
shall  terminate  (other  than the right to receive  the  Redemption  Price upon
delivery of such Series D Preferred Stock).

          8.  REISSUANCE  OF  SERIES  D  PREFERRED  STOCK.  Shares  of  Series D
Preferred  Stock that have been issued and  reacquired in any manner,  including
shares  purchased or redeemed or exchanged or converted,  shall (upon compliance
with any  applicable  provisions  of the laws of  Delaware)  have the  status of
authorized and unissued shares of preferred stock  undesignated as to series and
may be redesignated and reissued as part of any series of preferred stock (other
than Series D Preferred Stock).

          9. BUSINESS DAY. If any payment or conversion shall be required by the
terms  hereof to be made on a day that is not a Business  Day,  such  payment or
conversion shall be made on the immediately succeeding Business Day.

          10.  DEFINITIONS.  As used in this  Certificate  of  Designation,  the
following  terms shall have the  following  meanings  (with terms defined in the
singular  having  comparable  meanings  when used in the plural and VICE VERSA),
unless the context otherwise requires:

          "1997 Stock option plan" shall mean the 1997 stock purchase and option
     plan for key employees of kmc telecom holdings, inc. And affiliates, as the
     same may be amended from time to time.

          "Board of  Directors"  shall have the  meaning  ascribed  to it in the
     first paragraph of this Resolution.

          "Business Day" means any day except a Saturday, a Sunday, or other day
     on which  commercial  banks in the  State  of New  York or New  Jersey  are
     authorized or required by law or executive order to close.

          "Capital Stock" means, with respect to any Person, any and all shares,
     interests,  participations,   rights  in,  or  other  equivalents  (however
     designated  and whether  voting or  non-voting)  of, such Person's  capital
     stock  (but  excluding  any  debt  security  that  is  exchangeable  for or
     convertible into such capital stock).

          "Common  Stock"  shall have the  meaning  ascribed  to it in Section 2
     hereof.

          "Convertible  Securities"  shall mean any  evidences of  indebtedness,
     shares or securities convertible into or exchangeable for Common Stock.


                                       10



          "Corporation"  shall  have the  meaning  ascribed  to it in the  first
     paragraph of this Resolution.

          "Dividend  Payment  Date" means March 31,  June 30,  September  30 and
     December 31 of each year.

          "Dividend  Period" means the Initial Dividend Period and,  thereafter,
     each Quarterly Dividend Period.

          "Fair Market Value" per share of Common Stock as of a particular  date
     (the "Determination Date") shall mean: (i) if the Common Stock is listed or
     admitted  for  trading on a  national  securities  exchange,  then the Fair
     Market  Value shall be the average of the last 30 "daily  sales  prices" of
     the Common Stock on the principal national securities exchange on which the
     Common Stock is listed or admitted for trading on the last 30 Business Days
     prior to the  Determination  Date,  or if not  listed or traded on any such
     exchange,  then the Fair  Market  Value shall be the average of the last 30
     "daily sales prices" of the Common Stock on the Nasdaq  National  Market on
     the last 30 Business Days prior to the Determination Date (the "daily sales
     price" shall be the closing price for bona fide  transactions of the Common
     Stock at the end of each day); or (ii) if the Common Stock is not so listed
     or admitted to unlisted trading privileges or if no such sale is made on at
     least 25 of such days,  then the Fair Market  Value shall be as  reasonably
     determined by an investment  banking firm of recognized  national  standing
     selected  in good  faith  by the  Company's  Board of  Directors  or a duly
     appointed committee of the Board of Directors (which determination shall be
     reasonably  described in the written notice delivered to the holders of the
     Series D Preferred Stock).

          "Fully  Diluted"  shall  mean at any date as of which  the  number  of
     shares of Common  Stock is to be  determined,  all  shares of Common  Stock
     outstanding  at such date and the maximum  number of shares of Common Stock
     issuable in respect of  Convertible  Securities  and warrants,  options and
     other rights to purchase (directly or indirectly) shares of Common Stock or
     Convertible  Securities  (giving  effect  to the  then  current  respective
     conversion  prices)  outstanding  on such date (to the extent the rights to
     convert, exchange or exercise thereunder are presently exercisable).

          "High Yield Debt and Equity  Offering" shall have the meaning ascribed
     to it in Section 5 hereof.

          "Initial Dividend Period" means the dividend period commencing on, and
     including,  the  Series D  Preferred  Stock  Issue  Date and ending on, and
     excluding, the first Dividend Payment Date to occur thereafter.

          "Junior  Stock"  shall have the  meaning  ascribed  to it in Section 2
     hereof.

          "Liquidation  Preference"  shall have the  meaning  ascribed  to it in
     Section 1 hereof.

          "Option"  shall mean rights,  options,  or warrants to  subscribe  for
     purchase or otherwise acquire Convertible Securities or Common Stock.

          "Parity Preferred Stock" means,  collectively,  the Series A Preferred
     Stock, the Corporation's Series B Cumulative  Convertible  Preferred Stock,
     par value  $.01 per  share,  the  Series C  Preferred  Stock,  the Series D
     Preferred Stock and any other series of preferred stock which is determined
     to be "Parity Preferred Stock" by the Board of Directors.

          "Person" means any individual, firm, corporation, partnership, limited
     liability company, trust, incorporated or unincorporated association, joint
     venture,  joint stock  company,  governmental  body or other  entity of any
     kind.




                                       11



          "Qualified  Public  Offering"  shall mean the offer for sale of Common
     Stock  pursuant  to  an  effective  registration  statement  filed  by  the
     Corporation  under the  Securities  Act of 1933, as amended,  in any single
     transaction  or series of related  transactions,  in which the  Corporation
     receives   aggregate  gross  proceeds  (before  deduction  of  underwriting
     discounts and expenses of sale) of at least  $40,000,000  in the aggregate;
     provided  that the per share  price at which  such  shares  are sold in the
     offering (before deduction of underwriting  discounts and expenses of sale)
     is at least four times the conversion price of the Series A Preferred Stock
     which  would then be in effect if  determined  pursuant to the terms of the
     Series A  Preferred  Stock in effect on the  initial  issuance  date of the
     Series D Preferred  Stock  (whether or not any shares of Series A Preferred
     Stock are then outstanding).

          "Quarterly"  shall  mean the  quarterly  periods  commencing  on,  and
     including,  each Dividend  Payment Date and ending on, and excluding,  each
     next Dividend Payment Date occurring immediately thereafter, respectively.

          "Realization  Event" shall mean the  occurrence of (i) the sale of all
     or  substantially  all of the Common Stock or assets of the  Corporation or
     the  consolidation  or merger  of the  Corporation  with one or more  other
     corporations,  in any single transaction or series of related transactions,
     or (ii) the  closing of one or more  public  offerings  of Common  Stock in
     which the Corporation  receives  aggregate gross proceeds (before deduction
     of underwriting discounts and expenses of sale) of at least $40,000,000.

          "Series A Preferred Stock" means the Corporation's Series A Cumulative
     Convertible Preferred Stock, par value, $.0l per share.

          "Series C Preferred Stock" means the Corporation's Series C Cumulative
     Convertible Preferred Stock, par value, $.0l per share.

          "Series D Preferred  Stock"  shall have the meaning  ascribed to it in
     Section 1 hereof.

          "Series D  Preferred  Stock  Issue Date" means the first date on which
     the Series D Preferred Stock is issued by the Corporation.


          IN WITNESS  WHEREOF,  KMC  TELECOM  HOLDINGS,  INC.,  has caused  this
certificate to be duly executed by its Chief  Financial  Officer this 4th day of
November, 1997.

                                             KMC TELECOM HOLDINGS, INC.



                                             By: /S/ CYNTHIA WORTHMAN
                                                 --------------------------
                                                 Name:  Cynthia Worthman
                                                 Title:  Chief Financial Officer




                                       12