Nonalcoholic steatohepatitis (NASH) can be associated with progressive hepatic fibrosis and is an important cause of cirrhosis of the liver. Serum leptin levels are high in humans with NASH, and leptin can play a role in hepatic fibrogenesis. Our aim was to find out the correlation between the serum leptin level and the degree of histopathological changes of the liver in patients with NASH. This study was performed on 30 patients with NASH, and 10 normal subjects served as a control group.