Donald C. Haesloop, 61, a retired illustrator for the Naval Air Systems Command in Arlington, died Saturday at Potomac Valley Nursing Home in Rockville of amyotrophic lateral sclerosis, also known as Lou Gehrig's disease.

Mr. Haesloop was born and reared in Brooklyn and attended the Pratt Institute in New York. He came to the Washington area in about 1941, while serving on active duty with the Navy, and was assigned to the Navy Department's old Bureau of Hydrographics Office, now the Naval Oceanographic Office.

He joined the Naval Air Systems Command, which honored him for 25 years of government service, about 15 years ago as a draftsman and later became an illustrator. He retired last year for reasons of health.

Mr. Haesloop, who lived in Beltsville, was active in the Fourth Presbyterian Church in Bethesda. He also was a member of the Art Directors Club of Washington.

Survivors include his wife of 38 years, the former Betty Clement, of Beltsville; three daughters, Diane Sheldon of Herndon, Mary Ellen Oman of Pittsburgh and Betty Lee Haesloop of Silver Spring, and two grandsons.

The family suggests that expressions of sympathy be in the form of contributions to the Deacons Fund at Fourth Presbyterian Church in Bethesda.