Kathryn Jeanne Ostrow, 14, a student at Sidwell Friends School who aspired to be a writer and a pianist, died of cystic fibrosis Wednesday at Children's Hospital.

She was the daughter of Ronald J. Ostrow, a reporter with the Washington bureau of the Los Angeles Times, and Patricia Curran Ostrow, assistant director of the practice division of the American Occupational Therapy Association.

Kathryn was born in Los Angeles and moved here in 1966 with her family and lived in Bethesda.

She was a ninth-grade student at Sidwell Friends School but had been tutored at home for the past two years.

Kathryn had published poems in the Sidwell Friends Quarterly, the school journal, and had won a Library of Congress essay competition for the visually handicapped. She had written about her favorite recorded book.

She also had written an operetta and other music, and despite her illness had until recently spent several hours each day practicing at the piano.

In addition to her parents, she is survived by her grandparents, Mr. and Mrs. Edward Ostrow, of San Francisco, and Mr. and Mrs. James Jones, of Tempe, Ariz.

The family suggests that expressions of sympathy be in the form of contributions to the Cystic Fibrosis Foundation in Washington.