Non-alcoholic fatty liver disease (NAFLD) is an entity now recognized as one of the leading causes of asymptomatic chronic elevation of aminotransferase levels, which can, however, progress to more advanced forms of hepatic lesion and ultimately to liver failure. Insulin resistance is considered as having a central role in NAFLD pathogenesis, which is related with oxidative stress, abnormal production of cytokines and deregulation of fatty acid metabolism. In this article the authors make a brief review of the epidemiological data about NAFLD and insulin resistance, and their aetiological link, and treatment implications.