Non-alcoholic fatty liver disease (NAFLD) is often associated with features of the metabolic syndrome, carrying an increased risk to develop non-alcoholic steatohepatitis (NASH), the inflammatory form of liver steatosis. Epidemiological data confirm that obesity, diabetes, hypertension and hyperlipidemia are frequently found in NAFLD and worsen its prognosis because of increased risk of fibrotic evolution, eventually leading to liver cirrhosis. Recent studies confirm the close relationship between the metabolic syndrome and liver steatosis, and further support the detrimental role of oxidative stress and lipid peroxidation, which are pathophysiological processes present in both conditions. Novel diagnostic tools and life style modifications together with targeted therapeutic actions are urgently needed for the management of liver dysfunction in course of metabolic syndrome.