Irvin E. Sutphin, 50, a retired official of the Small Business Administration who was a lifelong resident of Northern Virginia, died of cancer Tuesday at Fairfax Hospital.

Mr. Sutphin was a native of Loudoun County and a graduate of Fairfax High School. He attended the University of Virginia and the American Institute of Banking.

He joined the old Vienna Trust Co. as head bookkeeper in 1945 and later was promoted to assistant cashier and branch manager before accepting similar posts with the National Bank of Fairfax in 1967.

A year later he became assistant cashier and branch manager with First and Merchants Bank in Vienna and worked there until joining the SBA's loan division as a commercial loan specialist in 1970. He retired for reasons of health last December.

Mr. Sutphin joined the Marine Corpos reserves in 1948 and was called to active duty during the Korean conflict. He retired from the reserves with the rank of chief warrant officer earlier this year.

He was a resident of Fairfax.

Survivors include his wife, Sally, two sons, Michael E. and R. Mark, and his mother, Dossie Sutphin, all of Fairfax, and a brother, Galen, of Branchville, N.J.

The family suggests that expressions of sympathy be in the form of contributions to the American Cancer Society.