The Rev. Robert F. Henry, 74, the retired rector of St. Barnabas Episcopal Church in Oxon Hill, died Sunday at the home of a daughter, Sue V. Mills, a member of the Prince George's County Council, in Oxon Hill. He had cancer.

Mr. Henry, who was born in Jackson, Mich., graduated from Nashota House College and Seminary in Wisconsin in 1933. He was ordained an Episcopal priest in Chicago in 1934 and served in parishes there until 1938, when he moved to the Washington area.

His first post here was in Oxon Hill, where he was rector of King George's Parish. During World War II, he was rector of St. John's Church and its chapel, St. Barnabas. He also conducted services at Fort Washington. In 1958, when St. Barnabas became a separate parish, Mr. Henry became its rector. He remained there until his retirement in 1979.

From 1945 until 1952, Mr. Henry was dean of the Southern Convocation, which includes all of the Episcopal churches in southern Maryland.

His wife, Myrtle, to whom he was married for 39 years, died in 1973.

In addition to Mrs. Mills, Mr. Henry's survivors include another daughter, Carla Rosenthal of Camp Springs; three brothers, Howard, of Phoenix, Ariz., Max, of Jackson, and Keith, of Ipsilanti, Mich.; three sisters, Ruth Mueller of Chicago, Betty Chalfant of Jackson and Mary Wolfe of Detroit, and four grandchildren.