William R. (Bill) Peifer, 66, a retired senior technician with the the TRW Corporation who was active in volunteer and patriotic organizations in Rockville, died of cancer Monday in the Rockville Nursing Home.

He was a cofounder of the Rockville Boys Baseball Association in 1952. He also coached baseball, basketball, and football teams in the Rockville Recreation Department's youth athletic program from the early 1950s to the mid 1960s.

Mr. Peifer served with Marines in the Southwest Pacific during World War II. He was a member of American Legion Post No. 86 in Rockville and was a past commander of post No. 9862 of the Veterans of Foreign Wars in Rockville.

He was a member of the Rockville Optimists Club.

Mr. Peifer joined the old Friedan Corporation, a calculator manufacturing concern, in 1945. The company was later, absorbed by TRW, and Mr. Peifer was a senior technician for 35 years before retiring earlier this year.

He was a native of Danville, Pa., and came to Washington in 1943. He had lived in Rockville for the past 29 years.

His wife, Bertha Cropp Peifer, died in 1962.

Survivors include a son, Kenneth, of Rockville; a daughter, Sandra McNamara of Omaha, Neb.; two sisters, Frances Morgan of Danville, Pa., and Dorothy Coulter of Phoenix, Ariz.; a half brother, Harold Everett of Danville, and two grandchildren.