In epidemiologic studies, human immunodeficiency virus (HIV)-infected men on antiretroviral therapy (ART) are at higher risk of incident diabetes mellitus compared with women with similar treatment histories. We used metabolomics to determine whether a sex difference in plasma amino acids, acylcarnitines, and organic acids predictive of diabetes and impaired energy metabolism is present in HIV-infected persons on long-term ART.We enrolled 70 HIV-infected adults (43% women) on efavirenz, tenofovir, and emtricitabine (Atripla) with HIV-1 RNA