Anthony G. Weinlein, 66, secretary-treasurer of the Service Employees International Union since 1976, died Tuesday at his home in Bethesda after a heart attack.

Mr. Weinlein began his union career in his native Milwaukee, where he was secretary-treasurer and later president of Local 150 of the old Building Service Employees International Union.

He joined the SEIU in 1943 as research director and subsequently became director of research and education, executive assistant to the president and executive assistant before being named secretary-treasurer.

The 600,000-member SEIU represents public employes, health-care workers and custodial and maintenance workers.

Mr. Weinstein had served on the Advisory Council on Health Insurance for the Disabled, the Task Force on Occupational Training and the 1971 White House Conference on Aging.

He participated in international conferences sponsored by the European Productivity Agency and the Organization of European Economic Cooperation and had served as a labor consultant in Japan for the Department of Labor.

Mr. Weinlein, an honors graduate of the University of Wisconsin, earned a master's degree and a doctorate from the University of Chicago.

He was a veteran of World War II.

Survivors include his wife, Mary, a daughter, Lisa, and a son, Eric (rick), all of Bethesda; two other sons, Michael and Kurt, both of Chicago; a brother, Frank, of Rhinelander, Wis., and a sister, Marjorie Fleck of Woodruff, Wis.

The family suggests that expressions of sympathy be in the form of contributions to the Robert Weinlein Memorial Fund at Cedar Lane Unitarian Church in Bethesda.