Abstract Two cases are presented with diseases considered to be atypical measles as described by Fulginiti and Kempe. Two siblings, 8 and 9 years old, received measles vaccine in 1963 according to a schedule of 2 injections of killed vaccine 1 month apart followed by 1 injection of live vaccine. In 1967 they contracted natural measles infection and developed a serious illness with high fever, exanthem, pneumonia and prostration. The patients recovered within 2 weeks. One patient has persistent infiltration in his left lung as revealed by X-ray examination. The diagnoses were substantiated epidemiologically and confirmed serologically.