Thomas J. Cosgrove, 52, an information officer in the Department of Labor and a former union official, died at Sibley Memorial Hospital Saturday following a heart attack.

Mr. Cosgrove was born in Bayonne, N.J., and educated at St. John's College, and the University of Notre Dame.

In 1961, Mr. Cosgrove became the director of education of the American Federation of State, County and Municioal Employees (AFL-CIO) in Washington. He remained in that position until 1965, when he went to work for the Office of Economic Opportunity.

In 1973, Mr. Cosgrove moved to the Department of Labor. He became assistant to the deputy undersecretary for legislative affairs and then was appointed director of information for the labor-management administartion, the position he held at the time of his death.

Survivors include his wife, Aurora Laura Casetti, of the home in Washington; a daughter, Deborah Catell, of Balitmore; two sons, Kevin, a Navy bandsman stationed at Treasure Island, San Francisco, and Gregory, a student at the University of West Virginia; his mother, Anna Boyle Cosgrove, of Washington; three sisters, Mrs. Terry Gowan, of Moore, S.C., Sister James Ann MSBT, of Billerica, Mass., and Nancy Cosgrove, of Washington, and a brother, Daniel, of Springfield, III.