Joseph T. Power, 61, president of the Operative Plasterers and Cement Masons International Association and a former U.S. delegate to the International Labor Organization (ILO) died of cancer Monday at his home in Falls Church.

Born and reared in Chicago, Mr. Power worked as a plasterer there.He later served as an official with Local 5 of the Plasterers and Cement Masons union in Chicago before being elected executive vice president of the International Association here in 1960. He became general executive board member of the association in 1963 and general president in 1970.

He had served as an adviser on labor matters to the State Department and to Presidents Ford and Carter. Last month, he was praised by President Reagan for his "leadership and instruction [that] have made it possible for the members of his union to find a good life for themselves and their families. He should be proud."

Mr. Power was appointed by President Ford to serve a three-year term on the Board of Visitors of the U.S. Military Academy and by President Carter to the National Institute of Building Sciences. He also served as a member of the Executive Council of the Building and Construction Trades Department of the AFL-CIO.

He served on a State Department mission to South America in 1973, was a public member of the State Department of Foreign Service Selection Board, and was a member of the U.S. delegation to the 57th session of the International Labor Organization.

In 1975, he received the Green-Murray Award of the Fraternal Order of Eagles. He was an active member of the board of directors of Joint Action in Community Services and the Cooperative Housing Foundation. Two years ago, he participated in the AFL-CIO's Free Trade Union Institute.

Survivors include his wife, Mary K., of Falls Church; two sons, John J., of Arlington and Joseph M., of Falls Church; four daughters, Kathryn van Helden of Washington, and Mary Ann Boyd, Joan McGuin and Sheila Power, all of Falls Church; three brothers, John, Edmond and Gerald Power, and four sisters, Katherine McDermott, Therese Paynter, Margaret McGurn and Joan Power, all of Chicago, and one granddaughter.

The family suggests that expressions of sympathy be in the form of contributions to Hospice of Northern Virginia in Arlington, or to the Catholic Church of St. Anthony's in Falls Church.