In order to address the critical knowledge gaps plaguing the field of NAFLD and NASH in HIV, we are proposing the following broad specific aims in our R01 application in response to the PAR-18-042. Specific Aim 1: To examine the prevalence of hepatic steatosis in a cross- sectional study on large cohort of HIV infected individuals. Specific Aim 2: To conduct a prospective observational study of 400 HIV infected individuals with histologically characterized NAFLD. Specific Aim 3: To carefully characterize liver histology in HIV infected individuals with biopsy proven NAFLD. Specific Aim 4: To conduct a multicenter, randomized, double-blind, placebo-controlled, clinical trial of a novel PPARα/γ agonist in 160 HIV infected individuals with biopsy proven NASH. Primary end point will be resolution of NASH with key secondary endpoints being (a) improvement in NAS by 2 points; (b) improvement in fibrosis; (c) improvement in aminotransferases; (d) improvement in cardiovascular risks; and (e) safety and tolerability.