Harry S. Kowalewski, 54, a civilian employe of the Army Department who was active in church organizations and the Knights of Columbus, died of cancer April 17 in Fauquier Hospital in Warrenton. He lived in Warrenton.

He had worked at the Army's Warrenton Training Center, where he was an instrumentation specialist, since 1953. Before that, he had been a television installer with Montgomery Ward and a radio station employe, both in his native Indiana. He was a graduate of the Valparaiso Technical Institute in Indiana and served in the Navy during World War II.

Mr. Kowalewski had been Virginia state membership chairman of the Knights of Columbus. He was a charter member of the Knights' Father Herman Veger Council No. 5561 where he had been Grand Knight and financial secretary.

He was a member of St. John the Evangelist Catholic Church in Warrenton where he was an usher, and a member of the building committee, the parish advisory board, and the Holy Name Society.

Survivors include his wife of 30 years, the former Jean Watt, two sons, Joseph and James, and three daughters, Sandie, Sally and Sharon Kowalewski, all of Warrenton; another daughter, Susan Bears of Frederick; three sisters, Jenny Jozwiak, Virginia Wantuck, and Florence Bilinski, and two brothers, Raymond and John, all of South Bend, Ind.; another brother, Julius of Pleasant Prairie, Wis., and two grandchildren.