ABSTRACT: BACKGROUND:Obesity and HIV disproportionately affect minorities and have significant health risks, but few studies have examined disparities in weight change in HIV-seropositive (HIV+) cohorts. OBJECTIVE:To determine racial and health insurance disparities in significant weight gain in a predominately Hispanic HIV+ cohort. METHODS:Our observational cohort study of 1214 nonunderweight HIV+ adults from 2007 to 2010 had significant weight gain [?3% annual body mass index (BMI) increase] as the primary outcome. The secondary outcome was continuous BMI over time. A 4-level race-ethnicity/insurance predictor reflected the interaction between race-ethnicity and insurance: insured white (non-Hispanic), uninsured white, insured minority (Hispanic or black), or uninsured minority. Logistic and mixed-effects models adjusted for baseline BMI, age, gender, household income, HIV transmission category, antiretroviral therapy type, CD4 count, plasma HIV-1 RNA, observation months, and visit frequency. RESULTS:The cohort was 63% Hispanic and 14% black; 13.3% were insured white, 10.0% uninsured white, 40.9% insured minority, and 35.7% uninsured minority. At baseline, 37.5% were overweight, 22.1% obese. Median observation was 3.25 years. Twenty-four percent of the cohort had significant weight gain, which was more likely for uninsured minority patients than insured whites [adjusted odds ratio = 2.85, 95% confidence intervals (CIs): 1.66 to 4.90]. The rate of BMI increase in mixed-effects models was greatest for uninsured minorities. Of 455 overweight at baseline, 29% were projected to become obese in 4 years. CONCLUSIONS AND RELEVANCE:In this majority Hispanic HIV+ cohort, 60% were overweight or obese at baseline, and uninsured minority patients gained weight more rapidly. These data should prompt greater attention by HIV providers for prevention of obesity.