Non-alcoholic fatty liver disease (NAFLD) is a frequent syndrome encompassing fatty liver alone and steatohepatitis (NASH). Often asymptomatic, the suspicion arises because of abnormal aminotransferases or a bright liver on abdominal ultrasound. It should be suspected during evaluation of associated conditions as obesity, diabetes or dyslipidaemia. The diagnostic evaluation must exclude other potential causes of liver disease and may include a liver biopsy, the only method able to confirm features of necroinflammation and fibrosis that define NASH and its prognostic implications. Indeed, the presence of necroinflammation has been associated with a significant risk of progression to cirrhosis and eventually hepatocellular carcinoma. Age >45 years, obesity and diabetes have also been associated with an increased risk of liver fibrosis and progression to cirrhosis. Given the high prevalence of NAFLD, general measures of life-style changes, focusing on exercise, diet, and total alcohol abstinence, should be implemented before a liver biopsy is considered.