We evaluated local reactions at 1, 2, and 4 months of age to bacille Calmette-Guérin vaccine given at birth to 1058 infants who were exposed to human immunodeficiency virus (HIV). No scar was discernible in 12 (12.4%) of 97 HIV-infected infants and 20 (2.1%) of 961 uninfected infants (relative risk, 5.9; 95% confidence interval, 3.0-11.8). This difference may reflect poorer immunogenicity in HIV-infected infants.