BACKGROUND: We conducted a systematic review and meta-analysis to evaluate the incidence and prevalence of 14 opportunistic infections (OIs) and other infections as well as the impact of antiretroviral therapy (ART) among human immunodeficiency virus (HIV)-infected children (aged <18 years) in low- and middle-income countries (LMICs), to understand regional burden of disease, and inform delivery of HIV services. METHODS: Eligible studies described the incidence of OIs and other infections in ART-naive and -exposed children from January 1990 to November 2013, using Medline, Global Health, Embase, Cumulative Index to Nursing and Allied Health Literature, Web of Knowledge, and Literatura Latino Americana em Ciências da Saúde databases. Summary incident risk (IR) and prevalent risk for each OI in ART-naive and ART-exposed children were calculated, and unadjusted odds ratios calculated for impact of ART. The number of OI cases and associated costs averted were estimated using the AIDS impact model. RESULTS: We identified 4542 citations, and 88 studies were included, comprising 55 679 HIV-infected children. Bacterial pneumonia and tuberculosis were the most common incident and prevalent infections in both ART-naive and ART-exposed children. There was a significant reduction in IR with ART for the majority of OIs. There was a smaller impact on bacterial sepsis and pneumonia, and an increase observed for varicella zoster. ART initiation based on 2010 World Health Organization guidelines criteria for ART initiation in children was estimated to potentially avert >161 000 OIs (2013 UNAIDS data) with estimated cost savings of at least US$17 million per year. CONCLUSIONS: There is a decrease in the risk of most OIs with ART use in HIV-infected children in LMICs, and estimated large potential cost savings in OIs averted with ART use, although there are greater uncertainties in pediatric data compared with that of adults.