James C. Gildea, 62, the assistant postmaster general for labor relations from 1973 until earlier this year, when he was named sectional center manager and postmaster at Inglewood, Calif., died May 15 at a hospital in Las Vegas after a heart attack.

He was stricken while flying to Los Angeles from a Postal Service conference in Chicago.

Mr. Gildea was born in Hazleton, Pa. He began his career in the trade union movement, working for the Textile Workers and the Retail Clerks Union. In 1941, he moved to Washington and joined what was then the Congress of Industrial Organizations. During World War II, he served in the Army in Europe.

In 1955, the CIO merged with the American Federation of Labor to form the AFL-CIO. In 1958, Mr. Gildea was named a special assistant to the late George Meany, the president of the AFL-CIO. In 1969, he became Meany's executive assistant.

In 1970, he was assigned as an adviser to the 1970 contract negotiations between what was then the Post Office Department and the unions. Talks had broken down and there occurred the first strike in the history of the postal service. Mr. Gildea was credited with playing a role in settling the issue and he later helped formulate the Postal Service Reorganization Act of 1970. This established the Postal Service as an independent agency.

In March 1973, Mr. Gildea joined the Postal Service as a special assistant for labor relations. In October of that year he was named assistant postmaster general for labor relations. For the next 12 years he was responsible for devising and carrying out the collective bargaining policies of the Postal Service.

Before joining the Postal Service, Mr. Gildea had been active in local labor affairs. He was a former vice president of the Maryland State and D.C. AFL-CIO and a vice president of the Washington Central Labor Council. He also had coordinated the activities of the local AFL-CIO Committee on Political Education in Montgomery County.

Mr. Gildea studied labor relations and economics at George Washington and American universities. While at the Postal Service, he attended management seminars at the Harvard and Stanford business schools and at the University of Virginia.

At his death, he still maintained a home in Chevy Chase and he was a member of the parish of the Shrine of the Blessed Sacrament Catholic Church. He was a former member of the Knights of Columbus.

Survivors include his wife, Mary Helen, of Chevy Chase; three children, Michael W., of Rockville, Annamarie Campbell of Arlington, and Thomas E., of Raleigh, N.C.; a sister, Rosemary Yurka of Hazleton, and one grandchild.