Nonalcoholic steatohepatitis (NASH) is a chronic liver disease that occurs in patients with no significant alcohol consumption, characterized for macrovesicular steatosis, hepatocellular necrosis, mixed inflammatory infiltrate and various grades of fibrosis and, in some cases, Mallory bodies. The prevalence of this disease is unknown; recent studies indicate that in the general population, incidence is about 3%, although the rates are higher in some subpopulations as are obesity and diabetes mellitus. The goal of this work was to determine the prevalence of non-alcoholic steatohepatitis in one sample of patients with the metabolic syndrome, patients at "Presidente Juárez" Regional Hospital. It was a cross-sectional and descriptive study in which, by means of random selection a sample of 110 patients with type 2 diabetes mellitus, arterial hypertension, obesity and dyslipidemia, alone or in combination was chosen. We carried out a clinical and laboratory evaluation, selecting those patients with persistent elevation of aminotransferases for whom additional studies were made, in order to exclude other causes of enzyme abnormality. Five patients were selected for percutaneous liver biopsy, all they had NASH. The prevalence of NASH was 4.54%. The clinical and laboratory characteristics of these patients will be discussed in the article.