Dr. Raymond L. Thurston, 68, a retired foreign service officer who had served as ambassador to both Haiti and Somalia, died of cancer Tuesday in a hospital in Sarasota, Fla. He was a resident of Siesta Key, Fla.

He gained a reputation as the model of the unruffled diplomat during his tenure as ambassador to Haiti from 1961 to 1963. An authority on Soviet and easter European affairs and former NATO adviser, he was appointed ambassador to Haiti because President John F. Kennedy was impressed with Dr. Thurston's work as a field evaluator of U.S. aid programs in Iran and India.

Dr. Thurston recommended that our aid program in Haiti be suspended. It was also during this time that the Kennedy administration temporarily suspended diplomatic relations with Haiti when Haitian President Francois (Popa Doc) Duvalier continued to hold the presidency after his term in office had expired.

During this first tour as ambassador, Dr. Thurston became highly admired by news reporters as a diplomat who, though introspective, spoke his mind and explained his positions with skill and care.

When relations on the ambassadorial level with Haiti resumed, that government refused to accept Dr. Thurston as U. S. ambassador. After teaching for a time, he was named ambassador to Somalia in 1965, a post he held until retiring four years later.

Dr. Thurston joined the Foreign Service in 1937. He served in Canada, Italy, India and Washington before going to Moscow in 1949. He spent two years there as the embassy's first secretary, then was counselor of embassy from 1950 to 1951.

He was deputy director and then director of the State Department's Office of Eastern European Affairs from 1952 to 1954, then served as deputy chief of mission in Athens, Greece, from 1955 to 1957.

From 1957 through 1960, he was counselor of the American Embassy in Paris and political adviser to Army Gen. Lauris Norstad who was commander of NATO forces.

Dr. Thurston taught political science at the University of Nevada from 1969 to 1971, then became affiliated with the Chapman College World Campus Afloat Program where he taught international studies and was a dean. He retired from the college in the mid-1970s.

He was a member of the American Foreign Service Association, the American Political Science Association, and DACOR.

Dr. Thurston was a native of St. Louis. A member of Phi Beta Kappa, he graduated with highest honors from the University of Texas in 1934, and earned a master's degree there a year later. He earned a doctoral degree in political science at the University of Wisconsin in 1937.

His marriage to the former Elizabeth Sherman ended in divorce.

Survivors include his wife, the former Gabriella Mariani, and a step-daughter, Francesca, both of Siesta Key; a daughter by his first marriage, Ruth Thurston of Philadelphia, and two sisters, Virginia Simmons of Bethesda, and Marjorie Kimes of Scottsdale, Ariz.