Arthur T. Nilsen Sr., a retired Baltimore elementary school educator and former Hamilton resident, died of cancer Sunday at his Ocean City home. He was 65.

Born in Baltimore and raised in the city's Hamilton section, Mr. Nilsen was a 1954 graduate of Polytechnic Institute. He served in the Navy from 1954 to 1957, and was a radarman aboard the destroyer USS Henry W. Tucker.

He earned his bachelor's degree in education from the University of Maryland, and a master's degree from Morgan State University in 1978.

Mr. Nilsen taught math at Mount Royal Elementary School and later at Barclay Elementary School, from which he retired in 1989. He had lived in Ocean City since 1997.

He had been an employee and volunteer with Meals on Wheels for several years, and had coached for the Hamilton Little League. He was a volunteer at Atlantic General Hospital in Berlin.

Mr. Nilsen was a member of Veterans of Foreign Wars Post 6406 in Rossville, and a former member of St. Luke's Lutheran Church in Parkville. He enjoyed duck woodcarving and gardening.

He was a member of St. Peter's Lutheran Church in Ocean City, where services were held yesterday.

Survivors include his wife of 44 years, the former Jacqueline Greensfelder; two sons, Arthur T. Nilsen Jr. of Perry Hall and David C. Nilsen of White Hall; a daughter, Jeanne M. Green of Newark, Worcester County; and three grandchildren.