William J. Vita Sr., 77, a retired office manager of the Diamond Cab Co. who was active in the local Italian-American community, died Wednesday at Prince George's General Hospital after a heart attack.

Mr. Vita had worked for Diamond Cab for more than 40 years and retired in 1972.

A lifelong Washington resident, he graduated from old Business High School in 1921. He attended the College of William and Mary in Virginia and graduated from Benjamin Franklin University here.

Mr. Vita was a founding member of the Casa Italiana Cultural Social Center in Washington and a former treasurer of the Lido Civic Club.

He attended St. Peter's Catholic Church here and was a member of the Holy Name Society of Holy Rosary Catholic Church in Washington.

His wife, Mary A., died in 1954.

Survivors include three sons, William J. Jr., of Lanham, Francis N., of Chevy Chase, and Joseph A., of District Heights; two daughters, Margaret J. McKnight of Silver Spring, and Catherine J. Sawdon of Wilmington, Del.; a sister, Alta Colabucci of Clinton, and 12 grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to Holy Rosary Church or to the Villa Rosa Nursing Home in Mitchellville, Md.