Retired Rear Adm. Edward J. Costello Jr., 81, a Naval Reserve supply corps officer who saw active duty in the Pacific theater in World War II and later worked as an engineering consultant here, died Wednesday at the National Naval Medical Center in Bethesda of complications following a colostomy.

Adm. Costello served in the Naval Reserve from 1936, when he became a lieutenant in the supply corps, until his retirement in 1963.

During World War II, he was called to active duty with the Naval Supply Depot in Norfolk, Va. He also served 15 months as part of a service squadron assigned to rebuild harbors on Midway Island after enemy assaults.

After the war, he was released from active duty and assigned to the Naval Powder Factory at Indian Head, Md. He later became commanding officer of a Naval Reserve supply company here. He was promoted to rear admiral in 1960.

A native of Verona, Pa., Adm. Costello attended the University of Pittsburgh, where he studied civil engineering. He specialized in heavy construction equipment, bridges, tunnels and shipbuilding and was a member of the MOLES, a society of tunnel engineers.

Before entering the Naval Reserve, he worked for the Wheeling Steel Corporation in West Virginia. After leaving military service, he was an engineering consultant in Washington for several years.

He was a member of the Army & Navy Club, the Society of Naval Architects and Marine Engineers, the American Legion and the Knights of Columbus, and was a life member of the Retired Officers Association and the Naval Reserve Officers Association.

Adm. Costello lived in Bethesda and was a member of St. Jane Francis de Chantal there. His wife, Helen Virginia, died in 1973.

Survivors include a son, Edward J. III, of Garland, Tex.; a sister, Marie L. Odgen, and six brothers, Raymond L., David C., George F., Clarance E., Ralph F., and Howard S., all of Pennsylvania, and two grandchildren.