UNITED STATES
                                SECURITIES AND EXCHANGE COMMISSION
                                      Washington, D.C. 20549

                                             FORM 144

                               NOTICE OF PROPOSED SALE OF SECURITIES
                       PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933






 ATTENTION: Transmit for filing 3 copies of this form concurrently with either placing an order with a
             broker to execute sale or CUSIP NUMBER executing a sale directly with a market maker.

- ----------------------------------------------------------------------------------------------------------------------------------
                                                                                      

1(a) NAME OF ISSUER (Please type or print)                     (b)  IRS IDENT. NO.         (c) S.E.C. FILE NO.
Factset Research Systems Inc.                                       13-3362547                 001-11869

- ----------------------------------------------------------------------------------------------------------------------------------

1(d) ADDRESS OF ISSUER     STREET        CITY               STATE              ZIP CODE
                                                                                                (e) TELEPHONE NO.
601 Merritt 7                            Norwalk,           CT                 06851
                                                                                                AREA CODE      NUMBER
                                                                                                  (203)       863-1500
 ---------------------------------------------------------------------------------------------------------------------------------

 2(a) NAME OF PERSON FOR   (b) IRS IDENT.      (c) RELATIONSHIP         (d)   ADDRESS      STREET     CITY      STATE     ZIP CODE
      WHOSE ACCOUNT             NO.                TO ISSUER
      THE SECURITIES ARE
      TO BE SOLD

 Estate of Howard E. Wille (1)     N/A           10% Stockholder            c/o Brian C. Wille,      New York    NY       10128
                                                                                Executor
                                                                            1088 Park Avenue
 ---------------------------------------------------------------------------------------------------------------------------------
                  INSTRUCTION: The person filing this notice should contact the issuer to obtain the
                                   I.R.S. Identification Number and the S.E.C. File Number.
- ----------------------------------------------------------------------------------------------------------------------------------






3 (a)              (b)

                                                                          SEC USE ONLY       (c)           (d)
                                                                          --------------
                                                                                           Number of
                                                                                            Shares
                                                                                           or Other       Aggregate
                                                                                             Units          Market
Title of the Class   Name and Address of Each Broker Through Whom the                     To Be Sold        Value
  of Securities      Securities are to be Offered or Each Market Maker    Broker-Dealer   (See instr.    (See instr.
    To Be Sold                who is Acquiring the Securities              File Number       3(c))          3(d))
- ------------------------------------------------------------------------------------------------------------------------
                    Morgan Stanley
      Common       1585 Broadway
      Stock        New York, NY 10036                                                    1,800,000     $64,080,000 (2)
                                                                                           

- ------------------------------------------------------------------------------------------------------------------------




    (e)            (f)             (g)

  Number of
    Shares
   or Other      Approximate    Name of Each
    Units       Date of Sale     Securities
 Outstanding     (See instr.      Exchange
 (See instr.        3(f))        (See instr.
    3(e))       (MO. DAY YR.)       3(g))
- -----------------------------------------------

                                    NYSE
            
47,872,882     9/27/2005

- -----------------------------------------------




INSTRUCTIONS:
  1. (a) Name of issuer.
     (b) Issuer's I.R.S. Identification Number. (c) Issuer's S.E.C. file
     number, if any. (d) Issuer's address, including zip code. (e) Issuer's
     telephone number, including area
code.

  2. (a) Name of person for whose account the securities are to be sold.
     (b) Such person's I.R.S. identification number, if such person is an
         entity.
  (c) Such person's relationship to the issuer (e.g., officer, director, 10%
     stockholder, or member of immediate family of any of the foregoing).
     (d) Such person's address, including zip code.

      3. (a) Title of the class of securities to be sold.
         (b) Name and address of each broker through whom the securities are
         intended to be sold. (c) Number of shares or other units to be sold
         (if debt securities, give the aggregate face amount). (d) Aggregate
         market value of the securities to be sold as of a specified date
         within 10 days prior to the filing of
            this notice.
         (e) Number of shares or other units of the class outstanding, or if
            debt securities the face amount thereof outstanding, as shown by
            the most recent report or statement published by the issuer.
         (f) Approximate date on which the securities are to be sold.
         (g) Name of each securities exchange, if any, on which the securities
            are intended to be sold.



     Potential persons who are to respond to the collection of information
contained in this form are not required to respond unless the form displays a
currently valid OMB control number.                         SEC 1147 (01-04)


TABLE I -- SECURITIES TO BE SOLD Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor: - ---------------------------------------------------------------------------------------------------------------------------------- Name of Person from Whom Acquired Amount of Title of Date you Nature of Acquisition (If gift, also give Securities Date of Nature the Class Acquired Transaction date donor acquired) Acquired Payment of Payment -------------------------------------------------------------------------------------------------------------------------------- Common Stock Sep. 1978 Property passed to Howard E. Wille 3,900,555 (3) N/A Property passed to the estate the estate on death on death of decedent of Howard E. Wille, co-founder of the issuer -------------------------------------------------------------------------------------------------------------------------------- INSTRUCTIONS: If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid. - --------------------------------------------------------------------------------------------------------------------------------- TABLE II -- SECURITIES SOLD DURING THE PAST 3 MONTHS Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold. - ---------------------------------------------------------------------------------------------------------------------------------- Amount of Name and Address of Seller Title of Securities Sold Date of Sale Securities Sold Gross Proceeds - ---------------------------------------------------------------------------------------------------------------------------------- None Estate of Howard E. Wille - ---------------------------------------------------------------------------------------------------------------------------------- REMARKS: (1) This Form 144 is also filed on behalf of the co-executors of the estate, Nancy E. Blair , P.O. Box 1214, Stamford, CT 06904-1214 and Brian C. Wille, 1088 Park Avenue, New York, NY 10128. Neither of Nancy E. Blair or Brian C. Wille have sold any securities of Factset within the past 3 months. (2) Aggregate Market Value in item 3(d) above is based upon the closing price of $35.60 for Factset common stock as of September 26, 2005. (3) 3,900,555 shares of Factset common stock passed directly to the estate on the death of Howard E. Wille. A non-managing interest in Wille Family Investments LLC also passed to the estate. Wille Family Investments LLC holds 1,500,000 shares of Factset comon stock. Brian C. Wille, co-executor of the estate, is the managing member of Wille Family Investments LLC. INSTRUCTIONS: ATTENTION: See the definition of "person" The person for whose account the securities in paragraph (a) of Rule 144. to which this notice relates are to Information is to be given not only be sold hereby represents by signing as to the person for whose account this notice that he does not know any the securities are to be sold but also material adverse information in regard to the as to all other persons included current and prospective operations in that definition. In addition, of the Issuer of the securities to be sold which has information shall be given as to not been publicly disclosed. sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice. Estate of Howard E. Wille Nancy E. Blair Brian C. Wille September 27, 2005 By:/s/ Nancy E. Blair By: /s/ Nancy E. Blair By:/s/ Brian C. Wille --------------------------------------------- --------------------------------------------------------------------------- DATE OF NOTICE Nancy E. Blair, Co-Executor Nancy E. Blair Brian C. Wille The notice shall be signed by the person for whose account the securities are to be sold. At least one copy of the notice shall be manually signed. Any copies not manually signed shall bear typed or printed signatures. - ------------------------------------------------------------------------------ ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001) - ------------------------------------------------------------------------------ SEC 1147 (01-04)