Nonalcoholic fatty liver disease (NAFLD) is associated with major cardiovascular risk factors, such as type 2 diabetes mellitus, obesity, dyslipidemia, hypertension, and insulin resistance, and has been recently considered to be a new component of metabolic syndrome and it serves as a criterion for the hepatic manifestation of the latter. The review considers the present-day views and approaches to diagnosing and treating NAFLD and its dangerous manifestation - fibrosis (sclerosis), which may lead to cirrhosis and hepatocellular carcinoma. Fibrogenesis is a widespread and universal process that is a final path of chronic inflammation of and damage to different tissues (including those of the liver and cardiovascular system). Although the mechanisms for developing NAFLD remain unclear, insulin resistance, an obesity-related slowly progressive inflammatory response, and elevated levels of free fatty acids with their lipotoxicity along with possible genetic, dietary, and environmental (lifestyle) factors play a key role in the pathogenesis of this disease. So it is important for patients at high risk for NAFLD or with existing liver disease to pay attention to their life style, proper balanced diet, and slow and gradual weight loss. At present there are drugs that can improve liver function. Success in NAFLD therapy will be determined by the identification of the most significant pathogenetic factors in a specific patient and by the purposeful action on them.