EXHIBIT 5




                                    June 28, 1995



BGS Systems, Inc.
128 Technology Center
Waltham, MA  02254-9111

Gentlemen:

   On your behalf, I have prepared a Registration Statement on Form S-8 (the
"Registration Statement") for filing with the Securities and Exchange
Commission relating to shares of the common stock, $.10 par value per share
("Common Stock"), of BGS Systems, Inc., a Massachusetts corporation (the
"Company"), issuable under the Company's 1995 Employee Stock Purchase Plan (the
"Plan").

   I have examined the Articles of Organization of the Company and all
amendments thereto in the office of the Secretary of State of Massachusetts,
all pertinent records of the meetings of the directors and stockholders of the
Company, the Registration Statement and such other documents relating to the
Company as I have deemed material for the purposes of this opinion.

   Based upon the foregoing, it is my opinion that the Company has duly
authorized for issuance the shares of Common Stock covered by the Registration
Statement to be issued under the Plan, as described in the Registration
Statement, and such shares, when issued in accordance with the terms of the
Plan, will be legally issued, fully paid and non-assessable.

   I hereby consent to the use of my name in the Registration Statement and the
filing of this opinion with the Securities and Exchange Commission in
connection with the Registration Statement.

                                    Sincerely,

                                    /S/ C. RUSSEL HANSEN, JR.
                                    ----------------------------------
                                    Vice President and General Counsel