Our objective was to compare obesity prevalence among human immunodeficiency virus (HIV)-infected adults receiving care and the U.S. general population and identify obesity correlates among HIV-infected men and women.Cross-sectional data was collected in 2009 to 2010 from 2 nationally representative surveys: Medical Monitoring Project (MMP) and National Health and Nutrition Examination Survey (NHANES).Weighted prevalence estimates of obesity, defined as body mass index ≥30.0 kg/m, were compared using prevalence ratios (PR, 95% confidence interval [CI]). Correlates of obesity in HIV-infected adults were examined using multivariable logistic regression.Demographic characteristics of the 4006 HIV-infected adults in MMP differed from the 5657 adults from the general U.S. population in NHANES, including more men (73.2% in MMP versus 49.4% in NHANES, respectively), black or African Americans (41.5% versus 11.6%), persons with annual incomes <$20,000 (64.5% versus 21.9%), and homosexuals or bisexuals (50.9% versus 3.9%). HIV-infected men were less likely to be obese (PR 0.5, CI 0.5-0.6) and HIV-infected women were more likely to be obese (PR1.2, CI 1.1-1.3) compared with men and women in the general population, respectively. Among HIV-infected women, younger age was associated with obesity (<40 versus >60 years). Among HIV-infected men, correlates of obesity included black or African American race/ethnicity, annual income >$20,000 and <$50,000, heterosexual orientation, and geometric mean CD4+ T-lymphocyte cell count >200 cells/μL.Obesity is common, affecting 2 in 5 HIV-infected women and 1 in 5 HIV-infected men. Correlates of obesity differ for HIV-infected men and women; therefore, different strategies may be needed for the prevention and treatment.