The Rev. Dr. Theodore Sylvester Ledbetter, 75, pastor of Plymouth Congregational United Church of Christ in Washington for 21 years until he retired in 1979 and an official of many church and service organizations, died of respiratory failure Nov. 11 at Carroll County General Hospital in Westminster, Md.

When Dr. Ledbetter took over as head of Plymouth Congregational in 1958, it was located at 17th and P streets NW and had a congregation of about 250 people. He supervised its move to 5313 North Capitol St. in 1961. By the time he retired, its membership numbered more than 1,500.

In his years as an active minister here, Dr. Ledbetter was a delegate to all of the General Synods of the United Church of Christ. In addition to other posts, he was a member of the Executive Council, president of the Stewardship Council, a director of the Board for Homeland Ministries, and a director of the Washington Metropolitan Area Council of Churches.

Dr. Ledbetter also was a director of the United Planning Organization, the United Givers Fund, the Inter-Religious Committee and the D.C. Central Democratic Committee. He was a delegate to the 1960 Democratic National Convention and a member of the Electoral College from the District for President Carter in 1976.

Dr. Ledbetter was born in Goliad, Tex. He graduated from Atlanta University and earned a bachelor's degree in divinity at the Graduate School of Theology at Oberlin College in 1935. He later received honorary doctorates from Ursinus College and Houston-Tillotson College.

From 1935 to 1937, he taught at what was then Tillotson College. From 1937 to 1947, he was pastor of Plymouth Congregational Church and superintendent of the Plymouth Social Settlement House in Louisville. From 1947 until he moved to Washington in 1958, he was minister of the Dixwell Avenue Congregational Church in New Haven, Conn.

Survivors include his wife, the former Orelia Washington, whom he married in 1936, of Silver Spring; two sons, Theodore S. Jr., of Austin, Tex., and Charles A., of Arlington, and two grandchildren. Another son, Leslie M. Ledbetter, died on July 29 this year.