The Advisory Committee on Immunization Practices (ACIP) recommends measles-mumps-rubella vaccine (MMR) for all persons asymptomatically infected with human immunodeficiency virus (HIV) and recommends that MMR be considered for all symptomatic HIV-infected persons who would otherwise be eligible for measles vaccine, because measles virus infection can cause severe illness and death in such persons. Serious or unusual adverse events in HIV-infected persons after receiving MMR have not been reported previously. This report summarizes the investigation of a case of progressive vaccine-associated measles pneumonitis in a person with acquired immunodeficiency syndrome and provides interim recommendations for the use of measles-containing vaccine among HIV-infected persons.