Using community-based surveillance data for pediatric human immunodeficiency virus (HIV) infection, we examined disease progression using survival analysis among perinatally HIV-infected children and children HIV-infected through a neonatal blood transfusion. As of December 31, 1991, 238 HIV-infected children (classified P-1 or P-2 according to the Centers for Disease Control and Prevention classification system) were identified. Median symptom-free survival time from birth to symptomatic infection (P-2) was different for perinatally acquired (n = 166) and neonatal transfusion-acquired (n= 72) infection (6.4 monthsvs.17.8 months, respectively;P< 0.001). Survival after development of symptomatic infection (P-2) did not differe by transmission mode. Survival differences from birth to death were significant atP< 0.005 (75% of perinatally HIV-infected children survived 44 monthsvs.71 months for transfusion-associated children). Although survival estimates improved for those receiving antiretroviral treatment, differences by mode were still observed. For perinatally HIV-infected children, mortality was highest in the first year of life (12%). Those remaining symptom-free beyond their first year demonstrated survival experiences similar to those for children with transfusion-associated infection.