Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatosis (NASH) are common conditions in the setting of HIV infection, especially if HCV coinfection or metabolic syndrome's features are present. The factors that contribute to the progression of NAFLD to NASH and fibrosis are not completely known and the role of antiretroviral therapy is especially controversial. Although the natural history of NASH in the setting of HIV infection is unknown, it may emerge as one of the leading causes of liver disease over the long term in these patients. Liver biopsy is still the gold standard for the diagnosis of NASH. Indeed, although non-invasive techniques are promising tools for the diagnosis of NAFLD, they do not assess liver damage. There is no specific therapy for NASH in HIV infection, as the role of glitazones has not been evaluated in these patients.