Jack N. Ferguson, 65, retired president and chairman of the board of Thompson Honor Dairy in Washington, died of cancer Friday at Carriage Hill of Silver Spring.

He had joined the dairy company in 1946 and was elected president in 1965. The diary, once one of the area's largest home-delivery suppliers, closed in 1971.

Mr. Ferguson was bron in El Paso, Tex. He was a graduate of Texas A & M and received a doctorate in physics from Cornell University. He was an engineer with the Corning Glass Works in Corning, N.Y., from 1940 until coming here in 1946.

He was a former treasurer of the milk Industry Foundation and had been a director of the Metropolitan Washington Board of Trade and the Union Trust Co.

He was a past president of the Cosmopolitan Club and the Boys Club of Greater Washington, which he had served as a director. He belonged to Chevy Chase Methodist Church.

He is survived by his wife, Jean, of the home in Chevy Chase; two sons, J. Leland, of Adelphi, and W. Scott, of Stamford, Conn.; his mother, Mrs. J. N. Ferguson, and a sister, Wilma Nail, both of El Paso; a brother, Dave H., of Jacksonville, Fla., and two granchildren.