Exhibit 99.1




       P R E S S                                            SIS Bancorp
    R E L E A S E


                              FOR IMMEDIATE RELEASE

Date:  October 22, 1997                   Contact:  Ting Chang, Vice President
                                                            Investor Relations
                                                                (413) 748-8271


              SIS Bancorp Reports 35% Increase In Pre-Tax Earnings


         Springfield,  MA - October  22,  1997,  8:30 a.m.  SIS  Bancorp,  Inc.,
(NASDAQ: SISB), the bank holding Company for Springfield Institution for Savings
("SIS  Bank"),  reported  net income of $3.2  million or $0.57 per share  (fully
diluted) for the quarter ended September 30, 1997, and $8.9 million or $1.58 per
share (fully diluted) for the nine months ended September 30, 1997.

         For the same periods in 1996, the Company  reported net income of $10.2
million  and $15.7  million,  respectively.  Net  income in 1996 was  positively
influenced by certain non recurring tax benefits.  Excluding the impact of these
tax items,  pre-tax  operating  earnings  for the quarter and nine months  ended
September 30, 1997 increased 35% and 51% respectively over 1996.

         In addition to reporting  earnings,  the Company announced the Board of
Directors'  declaration of a quarterly cash dividend payment of $0.14 per share.
The cash  dividend  will be payable on November 21, 1997 to holders of record as
of the close of business on November 4, 1997.

         "We are very  pleased  to report  another  quarter  of  increased  core
operating  earnings,"  said  F.  William  Marshall,  Jr.,  president  and  chief
executive  officer of SIS  Bancorp.  "The  results for the  quarter  reflect our
continued  ability to  differentiate  ourselves in western  Massachusetts as the
preferred  provider of financial  services.  As we enter new markets through the
merger with  Glastonbury  Bank and Trust, we remain focused on activities  which
generate growth in customers and build earnings momentum. Through these ends, we
believe SIS will build long term shareholder value."

         Total assets at September 30, 1997 equaled $1.5 billion, representing a
$104.4 million increase from December 31, 1996.  Expansion in the Company's loan
portfolio has  contributed to the growth in total assets since year end 1996. At
September 30, 1997, total gross loans were

                                                         





$686.3  million,  a 10% increase over year end 1996. The increase in total gross
loans  is  primarily  due  to  the  Company's  on-going  strategic  emphasis  on
increasing its home equity and commercial lending.

         At September 30, 1997,  total deposits were $1.0 billion,  representing
an increase of $52.1 million or 5% from December 31, 1996. Deposit growth during
the first nine months of 1997 resulted principally from the Company's efforts to
expand its delivery  systems and its on-going  promotion of the  convenience and
value of its products and services.

         The Bank's total  stockholders'  equity at  September  30, 1997 totaled
$107.0  million or 7.36% of total assets as compared to $101.9  million or 7.56%
of total assets at December 31, 1996. At September  30, 1997,  the Bank's Tier 1
Leverage  capital  ratio was 7.13%;  both the  Company  and the Bank  qualify as
"well-capitalized" under applicable regulatory standards.

         During the quarter, asset quality improved.  Total nonperforming assets
at September 30, 1997 declined  further to $4.9 million or 0.33% of total assets
and  represented a $2.7 million  reduction from year end 1996. The allowance for
possible loan losses totaled $18.4 million resulting in a reserve coverage ratio
of 440% of nonperforming loans, 379% of nonperforming assets, and 2.68% of total
gross loans outstanding.

         For the quarter and nine months ended  September 30, 1997, net interest
income was $12.5 million and $37.6 million, respectively. For comparable periods
in 1996,  the Company  reported net interest  income of $11.2  million and $31.3
million. Higher levels of earning assets in 1997 resulted in the increase in net
interest income.

         For the quarter and nine months ended September 30, 1997, provision for
possible  loan  losses  totaled  $0.4  million and $1.2  million,  respectively,
compared to $0.8 million and $2.2 million for the same periods in 1996.

         Noninterest  income for the quarter and nine months ended September 30,
1997 was $3.3  million  and $8.9  million,  respectively,  as  compared  to $2.9
million and $8.2 million over the same periods in 1996.

         Total  noninterest  expense  for the  quarter  and  nine  months  ended
September  30,  1997 was $10.3  million  and  $30.6  million,  respectively,  as
compared to $9.6  million and $27.6  million for the same  periods in 1996.  The
increase in total operating  expenses for the first nine months of 1997 reflects
costs related to the expansion of the Company's delivery systems,  including new
branch  locations,  an expanded ATM network,  and the introduction of new direct
marketing programs.

         For the first nine months of 1997,  the Company  recorded a net expense
of real  estate  operations  of $0.4  million as  compared to net income of $0.2
million for the same period in 1996. The increased  expense was  attributable to
charges,  recognized  during the first quarter of 1997,  in connection  with the
Company's continuing divestment of its real estate subsidiary.

         Commenting on the status of the  acquisition  of  Glastonbury  Bank and
Trust ("GBT"),  Marshall  indicated that the transaction is on schedule to close
by year end. Marshall further

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noted that the Company would be taking  certain steps to accelerate  the systems
conversions and full "back office" integration of GBT with SIS. As a result, the
combined  companies  anticipate  taking a pre-tax charge of  approximately  $4.0
million in merger  related  expenses  during the  fourth  quarter of 1997.  Full
integration  is expected to be completed  before the end of the first quarter of
1998. The Company's objective is to realize, as soon as possible,  the potential
synergies and future earnings related to this merger.

         SIS Bancorp, Inc. is a Massachusetts bank holding company for SIS Bank,
its sole subsidiary.  Established in 1827, SIS Bank serves its customers through
25 retail branches located throughout Hampden and Hampshire  Counties.  The Bank
services  $1.0  billion in  residential  mortgages  of which $761 million is for
others.

         All  inquiries  may be  forwarded  to Ms.  Ting Chang,  vice  president
investor relations and corporate planning, at (413) 748-8271.

         This news release  contains a forward looking  statement  regarding the
approximate  pre-tax charge for merger related  expenses,  which SIS anticipates
incurring in connection with the  acquisition of GBT. SIS cautions  readers that
this forward  looking  statement  involves  certain risks and  uncertainties  as
further  detailed in SIS'  current  report on Form 8-K dated  October 22,  1997,
which has been filed with the Securities and Exchange Commission.

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