Nonalcoholic fatty liver disease (NAFLD) encompasses a spectrum of diseases that ranges from simple steatosis to steatohepatitis (NASH), two entities with strikingly different outcomes. NAFLD is becoming one of the leading causes of chronic liver disease worldwide, but the real prevalence of the disease is still underestimated. NAFLD is strongly linked to insulin resistance and should be suspected in all patients with overweight, obesity, diabetes or other features of metabolic syndrome seeking medical care inside or outside Hepatology clinics. NASH is a slowly progressive fibrotic disease. Patients with NASH may develop cirrhosis, endstage liver disease and hepatocellular carcinoma. The overall and liver-related mortality are increased in patients with NASH compared to general population.