John Curry, 75, an administrative law judge with the U. S. Department of Agriculture for about 25 years, died Thursday at Fairfax Hospital after a short illness.

Since becoming an administrative law judge in 1945, Mr. Curry presided over such major decisions affecting agricultural commodities as the Packers and Stockyard Act, according to G. Osmond Hyde, the former chief examiner at the Agriculture department, who oversaw decisions by law judges.

The Packers and Stockyard Act regulated the methods of trading beef and poultry with the aim of insuring that farmers would get a fair share of the profit from the sale of the foodstuffs and that consumers would get high quality chickens and beef.

Mr. Curry joined the Agriculture Department in 1933 in South Carolina as a little attorney. At the time he was in charge of examining land titles in connection with land acquisitions by the Agriculture Department in North Carolina and South Carolina. The land purchased by the Agriculture Department was preserved as national forest land.

In 1939 Mr. Curry moved to the Washington office of the Agriculture Department, becoming an attorney in the regulatory division. While there he specialized in enforcing provisions of the Commodity Exchange Act, which regulates trading in stock future.

A member of the South Carolina and D.C. law bars, Mr. Curry was born in Charleston, S. C. He was a 1923 graduate of Citadel, the military college of South Carolina. In 1930 he received his law degree from Georgetown University.

He worked at the Southern Railway appraising shipping costs, while going to law school at Georgetown at night.

Mr. Curry retired rom the Agriculture Department in 1969.

He is survived by his wife, Erma E. Curry, of the home in Fairfax; two daughters, Mrs. Douglas A. Grier of Tyrone Pa., and Mrs. Perry Skjelbred of Wesporr, Conn.; and one grandchild, Geoffry Grier of Tyrone, Pa.