Non-alcoholic fatty liver disease (NAFLD) is the liver manifestation of metabolic syndrome and frequently accompanied with obesity, insulin resistance, hyperlipidemia and hypertension. NAFLD comprises a variety of clinical conditions ranging from simple steatosis (NAFL) to non-alcoholic steatohepatitis (NASH), with significant hepatic injury and possible progression to cirrhosis and hepatocellular carcinoma. The traditional "second hit" and the recent "multiple parallel hit" theories are the most popular explanations for the pathogenesis of NASH. NAFLD is usually diagnosed by ultrasonographic examination of the liver. For specific diagnosis of the extent and severity of NAFLD, in particular to determine NASH, the gold standard is still liver biopsy. Though, there are some promising non-invasive markers emerging for NAFLD diagnosis and assessment. Currently there is no specific therapy for NAFLD or NASH itself. Thus management of NAFLD mainly relies on initiating weight loss and on treatment of accompanying factors e.g. insulin resistance, hypertension or hyperlipidemia. In the present overview we aimed to summarize options for diagnosis and treatment of NAFLD and NASH based on the current literature.