The purpose of these analyses was to provide a prospective examination of the impact of HIV on birth weight using clinical, behavioral, psychosocial, and demographic correlates. HIV-positive (n = 319) and HIV-negative (n = 220) pregnant women matched for HIV risk factors (i.e., drug use and sexual risk behaviors) were interviewed during the 3rd trimester of pregnancy and 6 weeks postpartum. Medical chart reviews were also conducted for the HIV-seropositive pregnant women to verify pregnancy-related and birth outcome data. In a logistic regression analysis, model chi2(9, N = 518) = 124.8, p < .001, controlling for parity and gestational age, women who were HIV seropositive were 2.6 times more likely to have an infant with low birth weight. In addition, Black women and those who did not live with their partners were more than 2 times as likely to have infants with low birth weight, and those who smoked were 3.2 times more likely to have infants with low birth weight. Knowing that women with HIV, those who are Black, and those not living with a partner are at highest risk for adverse birth outcomes can help those in prenatal clinics and HIV specialty clinics to target resources and develop prevention interventions. This is particularly important for women with HIV because birth weight is associated with risk of HIV transmission from mother to child.