Lois Schaeffer Karasik, 55, a writer and staff member of the National Education Association since 1964, died of cancer Wednesday at Georgetown University Hospital.

For several years she had been coordinator of a pilot project for the development of video-disc instruction in elementary and junior high schools. The project is a joint venture of the NEA and the American Broadcasting Company.

Mrs. Karasik joined the NEA as a member of the staff of its National Association of Secondary School Principals. In 1969, she joined the staff of the NEA's Center for the Study of Instruction.

She was an editorial consultant to "Today's Education," the national journal of the NEA, and helped develop filmstrips and compile written works on the impact of the federal programs on education and teachers.

Mrs. Karasik, who was born in Chicago, was a 1945 cum laude graduate of Vassar College, where she earned a bachelor's degree in economics. She earned a master's degree in education at the Graduate Teacher's College of Winnetka in Winnetka, Ill., in 1949.

She was a junior high school teacher in Winnetka from 1949 to 1952, and lived in Japan and Austria where she taught English, before moving to this area in 1959. She lived in Bethesda.

Survivors include her husband, Daniel, and a son, Peter Raymond, both of Bethesda; a daughter, Elizabeth (Betsy) Alice Karasik of Brookline, Mass., and three sisters, Florence Bernstein of Highland Park, Ill., Marcella Fox of Winnetka, and Judith Provus of Northbrook, Ill.

The family suggests that expressions of sympathy be in the form of contributions to the Vincent T. Lombardi Cancer Center, Georgetown University Hospital, Washington, D.C., or to the Sloan-Kettering Cancer Institute, New York, N.Y.