Rodney Freaman Moulton, 57, an area resident since the early 1950s who was a writer-reporter with the Oliphant Washington Service, died of pneumonia Tuesday at Suburban Hospital in Bethesda.

He joined the service, which covers Washington for industries in the energy field, about 1968. Before that he had worked in the public information field with the National Aeronautics and Space Administration.

Mr. Moulton came to Washington from his native South Dakota to work as an aide to Sen. Francis Case (R-S.D.). Following the senator's death in 1962, Mr. Moulton went to work for Rep. R. Walter Riehlman (R-N.Y.), where he remained until Riehlman's defeat in 1964.

He was a graduate of the University of South Dakota and attended George Washington University's law school.

During World War Ii, Mr. Moulton was an intelligence specialist in the Army Air Forces with the 450th bombardment group in Europe.

He lived in Washington and District Heights before moving to Rockville about 15 years ago.

Survivors include his wife, Shirley, a son, Gary, and a daughter, Gewn, all of Rockville; another daughter, Gayle, of Alexandria, and two brothers, Ralph of Texas and Arden of South Dakota.

The family suggests that expressions of sympathy be in the form of contributions to the American Heart Association.