The response to Edmonston-Zagreb vaccine (titer, 5.4 log10 pfu) was evaluated among children in a study of perinatal transmission of human immunodeficiency virus (HIV) in Kinshasa. Acute postvaccination adverse events were monitored for 49 HIV-infected and 376 non-HIV-infected infants, and measles antibody responses were assessed by ELISA for 34 HIV-infected and 255 non-HIV-infected infants. There was no increase in the incidence of common symptoms 7-10 days after vaccination. HIV-infected infants were more likely to have detectable prevaccination measles antibody, and seroconversion after vaccination was somewhat lower in HIV-infected (76.5%) than non-HIV-infected infants (85.5%). Seroconversion rates did not differ among children with or without rhinitis or fever at vaccination. High-titer Edmonston-Zagreb vaccine given at 6 months of age has the potential to provide earlier protection against measles; however, this vaccine is no longer recommended for routine use, and two doses of standard-titer vaccines remains the preferred option for measles vaccination of HIV-infected infants.