Sylvia A. Lipnick, 69, a retired school librarian and teacher in Montgomery County, died of cancer March 24 at George Washington University Hospital.

She was vice president and director of the radio division of Forecast magazine, a Washington-Baltimore entertainment guide, of which her son, Richard W. Mostow, is publisher.

In 1959, Mrs. Lipnick became one of the first elementary school teacher-librarians in the Montgomery County public schools. Her headquarters were at Lone Oak School in Rockville. She then became librarian also at Meadow Hall School in Rockville.

Later she divided her time between Lone Oak and the central school library office in Rockville. She was one of those responsible for selecting children's literature for the county school system.

Active in county and state teachers associations, Mrs. Lipnick had served as president of the Montgomery County School Librarian Association in 1972. She retired in 1974.

She helped found Forecast magazine in 1964, and continued to be active in it until recently.

Born in New York City, Mrs. Lipnick was a graduate of the College of the City of New York. During the 1930s, she worked in the financial department of The New York Times.

She came here in 1942 with her first husband, Wolfe Mostow, a physicist and a cantor of Congregation Beth El in Bethesda. She was active in the sisterhood and library of the synagogue and sang in the choir.

Mrs. Lipnick was on the board of Takoma Park Public Library. She also was an assistant to the late Edith M. Stern, a writer on mental health subjects, and edited Mrs. Stern's book, "You and Your Aging parents."

In 1962, Mrs. Lipnick received a master's degree in library science from Catholic University, where she was elected to Beta Phi Mu, an honor group for library science.

She was divorced in the mid-1960s, and in 1971 she married Milton Lipnick, a retired physical chemist.

Mr. Lipnick had been a member of Temple Sinai since 1966, and was active in the sisterhood. She belonged to the Aleph Kallah study group, Hadassah and ORT, a Jewish service organization.

In addition to her husband, of the home in Silver Spring, and her son, of Bethesda, she is survived by a daughter, Phyllis Morrow, of New York City; a stepdaughter, Paula Goldsmid, of Oberlin, Ohio; a stepson; Lewis Lipnick, of Silver Spring, and a brother, William Aarons, of Woodland Hills, Calif.