Use of complementary and alternative medicine (CAM) is prevalent among HIV-positive individuals despite the success of antiretroviral treatments and limited evidence of CAM's safety and efficacy. To characterize the potential impact of CAM use on HIV care, we conducted a systematic review of 40 studies of CAM use among HIV-positive people. The goals of this review are to: (1) describe the demographic, biomedical, psychosocial and health behavior correlates of CAM use; (2) characterize patient-reported reasons for CAM use; and (3) identify methodological and conceptual limitations of the reviewed studies. Findings confirm that a high proportion of HIV-positive individuals report CAM use (M=60%). Overall, CAM use is more common among HIV-positive individuals who are men who have sex with men (MSM), non-minority, better educated and less impoverished. The use of CAM is also associated with greater HIV-symptom severity and longer disease duration. HIV-positive CAM users commonly report that they use CAM to prevent or alleviate HIV-related symptoms, reduce treatment side-effects and improve quality of life. Findings regarding the association between CAM use, psychosocial adjustment and adherence to conventional HIV medications are mixed. While the reviewed studies are instrumental in describing the characteristics of HIV-positive CAM users, this literature lacks a conceptual framework to identify causal factors involved in the decision to use CAM or explain implications of CAM use for conventional HIV care. To address this concern, we propose the use of health behavior theory and discuss implications of review findings for HIV care providers.