Mark N. Kernis, 26, a radio script writer and producer who also wrote frequently on jazz and popular music, died of leukemia Sunday at Georgetown University Hospital.

Mr. Kernis was born in Jersey City, N.J., and grew up in North Bergen, N.J. He came to the Washington area as a student at the University of Maryland in the fall of 1971 and graduated with a bachelor's degree in journalism in 1974.

While at Marylamd, Mr. Kernis was music director and a producer at WMUC, the university radio station. He also was entertainment arts editor of Argus/Dimension, a campus publication.

After graduation, Mr. Kernis began a career in radio and as a freelance writer and critic. He was assistant to the promotions director of WRC-WKYS AM-FM in Washington. From 1976 to 1977, he was public service director and then music director at WMAL-FM.

From the summer of 1977 until early this year, Mr. Kernis was a script writer for NUS in Gaithersburg. The firm makes video training films on energy. Mr. Kernis joined the staff of National Public Radio early this year to work as an associate producer on a pilot radio "magazine" show.

As a freelance writer and photographer, he wrote reviews on jazz and popular music for the Style section of The Washington Post. He also reviewed records for the Weekend section of this newspaper. He wrote the "Pop Stops" column for Washington Calendar magazine and also contributed photographs to that publication. He wrote reviews for several New Jersey newspapers and did interviews with jazz personalities for Sabin's Radio Free Jazz magazine.

Mr. Kernis' survivors include his wife, Paulette, of the home in Washington, and his parents, Morton and Norma Kernis, and a brother, Paul, all of Edison, N.J.