Dr. Lynn Ramsay Edminister, 88, a retired vice chairman of the U.S. Tariff Commission and a former special assistant to Secretary of State Cordell Hull, died of pneumonia Sunday at Suburban Hospital. He was a resident of Gaithersburg.

Dr. Edminster became a principal economist with the Agriculture Department in 1931. He joined the State Department in 1936 and two years later was named special economic assistant to Hull. He held that post until 1942.

He was a member of the Tariff Commission from 1942 until retiring from the government in 1955, serving for much of this time as the commission's vice chairman. During those years, he also represented the government at trade conferences overseas.

Since 1955, Dr. Edminster had been an economic consultant to industry and research organizations. He had lectured at the University of Virginia and elsewhere.

He was a member of the Columbia Country Club.

Dr. Edminster was a native of Illinois. He was a 1916 graduate of Harvard University and later earned a doctorate at the Brookings Institution. After serving in the Army in World War I, he was an economist with the Tariff Commission. He then joined the staff at the Brookings Institution, where he worked until his return to the government.

Survivors include his wife, the former Lucile Forsythe, of Gaithersburg; a daughter, Margaret Kimmel of Washington; a sister, Winn Spinner of Bainbridge, Was., and three grandchildren.