1

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549



                                  SCHEDULE 13D

                    UNDER THE SECURITIES EXCHANGE ACT OF 1934

                            SI FINANCIAL GROUP, INC.
-------------------------------------------------------------------------------
                                (Name of Issuer)


                     COMMON STOCK, PAR VALUE $0.01 PER SHARE
-------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                    78426W102
                                 --------------
                                 (CUSIP Number)

                               RHEO A. BROUILLARD
                      PRESIDENT AND CHIEF EXECUTIVE OFFICER
                            SI FINANCIAL GROUP, INC.
                                 SI BANCORP, MHC
                                 803 MAIN STREET
                         WILLIMANTIC, CONNECTICUT 06226
                                 (860) 423-4581
 ------------------------------------------------------------------------------
(Name, Address and Telephone Number of Person Authorized to Receive Notices and
                                Communications)

                               SEPTEMBER 30, 2004
                              --------------------
             (Date of Event which Requires Filing of this Statement)

      If the filing person has previously filed a statement on Schedule 13G to
report the acquisition that is the subject of this Schedule 13D, and is filing
this schedule because of Sections 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g),
check the following box |_|.

      NOTE: Schedules filed in paper format shall include a signed original and
five copies of the schedule, including all exhibits. See Rule 13d-7 for other
parties to whom copies are to be sent.






                         (Continued on following pages)



 2



CUSIP No.  78425W102



                                  SCHEDULE 13D

-------------------------------------------------------------------------------
   1   NAMES OF REPORTING PERSONS
       I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

             SI BANCORP, MHC

             06-1596073

-------------------------------------------------------------------------------
   2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP                (a) /_/
                                                                       (b) /_/

-------------------------------------------------------------------------------
   3   SEC USE ONLY
-------------------------------------------------------------------------------
   4   SOURCE OF FUNDS
                      OO
-------------------------------------------------------------------------------

   5   CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO
       ITEM 2(d) or 2(e)                                                   /_/

-------------------------------------------------------------------------------
   6   CITIZENSHIP OR PLACE OF ORGANIZATION
             UNITED STATES

-------------------------------------------------------------------------------
                                 7  SOLE VOTING POWER
  
      NUMBER OF                       7,286,975
       SHARES
    BENEFICIALLY                -----------------------------------------------
      OWNED BY                   8  SHARED VOTING POWER
        EACH
      REPORTING                             0
       PERSON                   -----------------------------------------------
        WITH                     9  SOLE DISPOSITIVE POWER

                                         7,286,975
                                -----------------------------------------------
                                10   SHARED DISPOSITIVE POWER
                                             0
-------------------------------------------------------------------------------
  11   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
             7,286,975
-------------------------------------------------------------------------------

12   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES  /_/
-------------------------------------------------------------------------------
13   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11);
             58%
-------------------------------------------------------------------------------
14   TYPE OF REPORTING PERSON
             HC, CO
-------------------------------------------------------------------------------



                                        2

 3



ITEM 1.  SECURITY AND ISSUER.
         --------------------

     This Schedule 13D relates to the shares of common stock, par value $.01 per
share, of SI Financial Group, Inc.(the "Issuer" or the "Company"), a federally
chartered corporation. The principal executive office of the Issuer is located
at 803 Main Street, Willimantic, Connecticut 06226.

ITEM 2.  IDENTITY AND BACKGROUND.
         ------------------------

     This  Schedule  13D is  being  filed by SI  Bancorp,  MHC  (the  "MHC"),  a
federally  chartered mutual holding company.  The MHC's principal business is to
hold a majority of the Issuer's shares of common stock.  The principal office of
the MHC is located at 803 Main Street,  Willimantic,  Connecticut 06226.  During
the past five years the MHC has not been convicted in a criminal  proceeding nor
has the MHC been a party to a civil  proceeding of a judicial or  administrative
body of competent  jurisdiction and, as a result of such proceeding,  been or is
subject to a judgment,  decree or final order enjoining future violations of, or
prohibiting or mandating activities subject to, federal or state securities laws
or finding any violation with respect to such laws.

     Attached as Schedule I hereto and  incorporated  herein by  reference  is a
list containing certain  information with respect to each director and executive
officer  of the  MHC  (the  "Insiders").  To the  MHC's  knowledge,  each of the
Insiders is a United States  citizen,  and none of such Insiders has, during the
past five years,  been  convicted in a criminal  proceeding  (excluding  traffic
violations  or similar  misdemeanors)  nor have the  Insiders  been a party to a
civil proceeding of a judicial or administrative body of competent  jurisdiction
and, as a result of such proceeding, been or is subject to a judgment, decree or
final  order  enjoining  future  violations  of,  or  prohibiting  or  mandating
activities subject to, federal or state securities laws or finding any violation
with respect to such laws.

ITEM 3.  SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.
         --------------------------------------------------

     On September 30, 2004, the Issuer sold 5,025,500  shares of common stock to
the public at $10.00 per share and sold 7,286,975  shares of common stock to the
MHC at $0.01 per share. The funds for the purchase of the shares by the MHC came
from its  initial  capitalization.  All  purchases  by the  Insiders  were  from
personal funds.

ITEM 4.  PURPOSE OF TRANSACTION.
         -----------------------

     The primary purpose of the stock offering was to establish a structure that
will result in the raising of additional  capital to support  future lending and
operational growth and may also support possible future branching  activities or
acquisitions.  The stock offering will also enable the employees and officers of
Savings Institute Bank and Trust Company (the "Savings Bank"),  the wholly-owned
subsidiary of the Company, to obtain an equity ownership interest in the Savings
Bank. Because the Issuer only sold a minority of the common stock to the public,
the

                                        3

 4



Savings  Bank's  mutual  form of  ownership  and its  ability  to remain an
independent savings bank and to provide community-oriented financial services is
expected to be preserved.

     Although  the MHC and the  Insiders  intend  to  exercise  their  rights as
stockholders,  neither  the MHC nor the  Insiders  currently  have any  plans or
proposals  which relate to or would result in: (a) the acquisition by any person
of additional  securities of the Issuer or the  disposition of securities of the
Issuer;  (b)  an  extraordinary   corporate  transaction,   such  as  a  merger,
reorganization or liquidation,  involving the Issuer or any of its subsidiaries;
(c) a sale or  transfer  of a material  amount of assets of the Issuer or any of
its subsidiaries; (d) any change in the present Board of Directors or management
of the Issuer,  including any plans or proposals to change the number or term of
directors  or to fill any  existing  vacancies  on the Board;  (e) any  material
change in the present  capitalization or dividend policy of the Issuer;  (f) any
other  material  change in the  Issuer's  business or corporate  structure;  (g)
changes in the Issuer's charter, bylaws or instruments  corresponding thereto or
other actions which may impede the  acquisition  of control of the Issuer by any
person;  (h) causing a class of  securities  of the Issuer to be delisted from a
national  securities exchange or to cease to be authorized or to be quoted in an
inter-dealer  quotation system of a registered national securities  association;
(i) a class of equity securities of the Issuer becoming eligible for termination
of  registration  pursuant to Section  12(g)(4) of the Exchange  Act; or (j) any
action similar to any of those enumerated above.

     In the  future,  the MHC and/or the  Insiders  may  determine  to  purchase
additional  shares of the  Issuer's  common  stock (or other  securities  of the
Issuer) or the MHC and/or  the  Insiders  may  determine  to sell  shares of the
Issuer's  common  stock.  Any such  determination  will  depend  on a number  of
factors,  including  market  prices,  the  Issuer's  prospects  and  alternative
investments.

ITEM 5.  INTEREST IN SECURITIES OF THE ISSUER.
         -------------------------------------

     (a) - (b) The MHC  beneficially  owns  (with sole  voting  and  dispositive
power)  7,286,975  shares of the Issuer's common stock or 58% of the outstanding
shares.  The following  table provides  information  about the shares of Company
common stock that may be  considered to be owned by each Insider as of September
30,  2004.  A person may be  considered  to own any shares of common  stock over
which he or she has, directly or indirectly, sole or shared voting or investment
power. Unless otherwise indicated, each of the named individuals has sole voting
and investment power with respect to the shares shown.

                                        4

 5





                                           NUMBER OF    PERCENT OF
                                            SHARES      COMMON STOCK
NAME                                         OWNED      OUTSTANDING
-----                                    -------------  --------------

Rheo A. Brouillard......................       23,850(1)          *
Robert C. Cushman, Sr...................        5,000             *
Roger Engle.............................       14,073(2)          *
Donna M. Evan...........................       10,000             *
Robert O. Gillard.......................       12,427(3)          *
Henry P. Hinckley.......................        5,000             *
Brian J. Hull...........................       15,302             *
Steven H. Townsend......................            -             *
Everett A. Watson.......................          525(4)          *

* Represents less than 1% of shares outstanding.
 (1)Includes 1,000 shares held by Mr. Brouillard's spouse and 2,850
    shares held by Mr. Brouillard's spouse's individual retirement
    account.
 (2)Includes 73 shares held by Mr. Engle's spouse in a custodial account
    for the benefit of Mr. Engle's children.
 (3)Includes 4,409 shares held by Mr. Gillard's spouse's individual retirement 
    account.
 (4)Includes 25 shares held by Mr. Watson's spouse.

      (c) Other than the purchase of such shares by the MHC and the Insiders on
      September 30, 2004, neither the MHC nor the Insiders have effected any
      transaction in the Issuer's common stock within the past 60 days.

      (d) No person other than the MHC has the right to receive or the power to
      direct the receipt of dividends from, or the proceeds from the sale of,
      the securities owned by the MHC as described in Item 5(a)-(b) above.

ITEM 6.  CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS, OR RELATIONSHIPS WITH RESPECT
         ----------------------------------------------------------------------
         TO SECURITIES OF THE ISSUER.
         ----------------------------

      Not applicable.

ITEM 7.  MATERIAL TO BE FILED AS EXHIBITS.
         ---------------------------------

      Not applicable.

                                        5

 6



                                    SIGNATURE
                                    ---------

      After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.


                                       SI BANCORP, MHC


Date: October 8, 2004             By:  /s/ Brian J. Hull                      
                                      ----------------------------------------
                                       Brian J. Hull
                                       Executive Vice President, Chief Financial
                                        Officer and Treasurer






                                        6

 7


                                   SCHEDULE I

               DIRECTORS AND EXECUTIVE OFFICERS OF SI BANCORP, MHC
               ---------------------------------------------------

      The names, business address and present principal occupation of each
director, executive officer and controlling person of SI Bancorp, MHC are set
forth below. All persons are citizens of the United States.




NAME                  BUSINESS ADDRESS            PRINCIPAL OCCUPATION
                                            

Rheo A. Brouillard    803 Main Street             President and Chief Executive Officer of SI Financial 
                      Willimantic, Connecticut    Group, Inc., SI Bancorp, MHC and 
                                                  Savings Institute Bank and Trust Company.

Brian J. Hull         803 Main Street             Executive Vice President, Chief Financial Officer and
                      Willimantic, Connecticut    Treasurer of SI Financial Group, Inc. and SI Bancorp,
                      06226                       MHC and Executive Vice President and Chief Financial 
                                                  Officer of Savings Institute Bank and Trust Company.

Robert C. Cushman, Sr 803 Main Street             Director of SI Financial Group, Inc., SI Bancorp, MHC
                      Willimantic, Connecticut    and Savings Institute Bank and Trust Company; retired.
                      06226

Roger Engle           803 Main Street             Director of SI Financial Group, Inc., SI Bancorp, MHC
                      Willimantic, Connecticut    and Savings Institute Bank and Trust Company; retired.
                      06226

Donna M. Evan         803 Main Street             Director of SI Financial Group, Inc., SI Bancorp, MHC
                      Willimantic, Connecticut    and Savings Institute Bank and Trust Company; sales
                      06226                       manager for Nutmeg Broadcasting, the owner of a commercial radio
                                                  station located in Willimantic, Connecticut.

Robert O. Gillard     803 Main Street             Director of SI Financial Group, Inc., SI Bancorp, MHC and
                      Willimantic, Connecticut    Savings Institute Bank and Trust Company; Chairman
                      06226                       of The O.L. Willard Co., Inc., a full-service hardware
                                                  store with locations in Storrs and Willimantic,
                                                  Connecticut.

Henry P. Hinckley     803 Main Street             Chairman of the Board of SI Financial Group, Inc., SI
                      Willimantic, Connecticut    Bancorp, MHC and Savings Institute Bank and Trust
                      06226                       Company; President of J.P. Mustard Agency, Inc., an
                                                  insurance agency located in Willimantic, Connecticut.

Steven H. Townsend    803 Main Street             Director of SI Financial Group, Inc., SI Bancorp, MHC
                      Willimantic, Connecticut    and Savings Institute Bank and Trust Company;
                      06226                       Chairman of the Board and Chief Executive Officer of
                                                  United Natural Foods, Inc., a distributor of natural and
                                                  organic foods and related products located in Dayville,
                                                  Connecticut.

Everett A. Watson     803 Main Street             Director of SI Financial Group, Inc., SI Bancorp, MHC
                      Willimantic, Connecticut    and Savings Institute Bank and Trust Company; retired.
                      06226



                                        7