A study of 568 children aged <5 years who commenced nonnucleoside reverse-transcriptase inhibitor-based antiretroviral therapy in resource-limited settings revealed good early outcomes. After 12 months of antiretroviral therapy, survival probability was 0.89 (95% confidence interval, 0.86-0.92), with no significant difference among children stratified on the basis of baseline immunological levels; 62% attained a CD4 cell percentage >25%, and 7% continued to have a CD4 cell percentage <15%.