Tilmer O. Engebretson, 64, a retired Foreign Agricultural Service attache, died of cancer Wednesday at Sibley Memorial Hospital.

His last Agriculture Department assignment was as attache in Ankara, Turkey, from 1974 to 1976. He lived in Great Falls, Va.

Born in Starbuck, Minn., Mr. Engebretson was a graduate of St. Olaf College in Northfield, Minn. He came to Washington in 1942 as a statistician with the Labor Department and joined the Agriculture Department a year later as an agricultural economist.

After serving briefly with the Commerce Department as a agricultural statistician in 1946, Mr. Engebretson joined the State Department where he was an economic analyst on duty in Seoul, Korea, until 1949.

He returned to the Agriculture Department where he was assigned to the Foreign Service as regional specialist for the Far East.

From 1954 to 1956, Mr. Engebretson was agricultural attache in New Delhi, India. This was followed by four years as attache in Salisbury, Rhodesia, and five years in Tehran, Iran.

He returned to work at Foreign Agricultural Service offices here until his last assignment in Ankara.

He is survived by his wife, Rac G., and a son, Tilmer O. Jr., both of the home; another son, Peter R., of Baltimore; two sisters, Mabel Peterson, of Starbuck, and Ruth Helgoe, of Halstad, Minn., and two brothers, Edwin J. and John A., both of Starbuck.

The family suggests that expressions of sympathy may be in the form of contributions to the National Lutheran Home in Washington or the American Red Cross blood program.