Kate Mostel, an actress and author, died of a heart attack yesterday at her apartment in Manhattan. She was 67 years old.

Mrs. Mostel, the widow of Zero Mostel, began her theatrical career as a child actress and dancer, appearing as Katherine Harkin. She danced with the Littlefield Ballet Company of Philadelphia. She also appeared as a member of the Rockettes at Radio City Music Hall, where she first met Mr. Mostel, whom she married in 1944.

As an actress, she appeared on Broadway in the 1950's in a play by Dorothy Parker and Arnaud d'Usseau, ''The Ladies of the Corridor,'' and with Walter Matthau and Wally Cox in a revival of ''Three Men on a Horse.''
She and Madeline Gilford, the wife of the actor Jack Gilford, wrote ''170 Years of Show Business,'' which was published by Random House in 1978.

Source: NY Times Obit 1/23/1986