Low serum micronutrient levels are common in HIV-positive individuals and have been associated with immune impairment, HIV disease progression, and increased mortality. Studies of micronutrient supplementation have yielded conflicting results, although several large trials suggest that multivitamin supplements, but not vitamin A, may decrease morbidity and mortality in some HIV-positive populations. Studies also suggest that antioxidant supplementation may decrease markers of oxidative stress in individuals with HIV, while selenium may enhance immune function by modulating cytokine production. Clearly, more research is needed, but current knowledge supports the use of a multivitamin supplement as a low-cost adjunct to antiretroviral treatment.