Lillian Smith McIlvaine, 67, a former government employe and a resident of the Washington area for more than 40 years, died at her home in Falls Church Saturday following a heart attack.

Mrs. McIlvaine was born in Bonham, Tex. She attended Texas State College for Women and then was secretary to the mayor of Bonham.

She moved to Washington in 1938 at the suggestion of the late Rep. Sam Rayburn (D-Tex.), a former speaker of the House of Representatives and a longtime friend. She went to work for the old Works Progress Administration. She remained there until shortly after her marriage in 1939 to James L. McIlvaine, a founder and former president of the Suburban Savings & Loan Association.

Mrs. McIlvaine devoted most of her time to raising her family. She also was active in parents groups at St. Stephen's Episcopal Day School for Boys in Alexandria. She had lived in Falls Church for the past 35 years.

In addition to her husband, of Falls Church, survivors include a daughter, Karen M. Durfee of Pasadena, Calif.; two sons, James L. Jr., of McLean, and Don C., of Fairfax; two brothers, Kenneth W. Smith of Tallahassee, Fla., and Sidney H. Smith of Corpus Christi, Tex.; her stepmother, Thelma Smith of Dallas; a half sister, Beth Broyhill of San Francisco, and six granchildren.

The family suggests that expressions of sympathy be in the form of contributions in Mrs. McIlvaine's memory to the Fairfax Hospital Association Foundation.