Between 2000 and 2005, 84 HIV-infected children were referred to Children's National Medical Center; 28 were born to immigrant mothers, 89% of whom were of African descent. Rates of antiretroviral prophylaxis were low regardless of maternal origin. Nonimmigrant mothers (30.4%) used illicit drugs (P < 0.001), and 50% of immigrant mothers breast-fed their children (P < 0.001). These data can guide intervention strategies.