Genevieve Kornacki (Janet) Reed, 56, a registered nurse who was active in civic, political and volunteer organizations in Montgomery County, died Saturday at her home in Kensington. She had cancer.

Mrs. Reed worked at Sylvan Manor Health Care Center in Silver Spring from late 1980 until retiring in June 1981. In the 1970s, she worked at the Kensington Gardens nursing home and in the early 1950s at the old Garfield Hospital in Washington.

She had been active in PTA organizations in Montgomery County and a tutor with the Literacy Council of Montgomery County. She also was an English tutor with Polish-speaking students in the county schools.

Mrs. Reed had been a precinct judge in the county for the last 12 years and a volunteer in campaigns of for Sen. Charles McC. Mathias and former Rep. Gilbert Gude, both Republicans.

She had been a Cub Scout den mother and a Campfire Girls group leader. At the time of her death, she was secretary of the Kensington Heights Citizens Association and a member of the Kenmont Recreation Club.

Mrs. Reed was born in Schenectady, N.Y. She was a graduate of the Mount Sinai School of Nursing in New York City. She moved to the Washington area in 1950. She was a member of the parish of Holy Redeemer Catholic Church.

Survivors include her husband, Donald E. Reed Sr., three sons, Donald, Richard and David, and two daughters, Stephanie and Elizabeth, all of Kensington; another daughter, Martha, of Madison, Wis.; her mother, Katherine Kornacki, a brother, Joseph Kornacki, and three sisters, Pauline Byster, Victoria Zakriski and Gertrude Barry, all of Schenectady, and another sister, Josephine Symanski of Burlington, Vt.