The last comprehensive literature review to examine the effectiveness of family planning (FP) services in delivering STI and HIV prevention and care was published in 2000. This review updates that report by examining evidence of the impact of integrating any component of STI or HIV prevention, care, and treatment into a family planning setting in developing countries. Forty-four reports were identified from a comprehensive search of published databases and "grey literature". The weight of evidence demonstrates that integrated services can have a positive impact on client satisfaction, improve access to component services, and reduce clinic-based HIV-related stigma, and that they are cost-effective. Evidence of FP services reaching men and adolescents and of their impact on health outcomes is inconclusive. Several studies found that providers frequently miss opportunities to integrate care and that the capacity to maintain the quality of care is also influenced by many programmatic challenges. The range of experiences indicates that managers need to determine appropriate health-care service-delivery models based on a consideration of epidemiological, structural, and health-systems factors.