Non-alcoholic fatty liver disease (NAFLD) is a complex of a wide spectrum of liver pathology--from steatosis alone, to cirrhosis and liver cancer. The pathogenic concept of NAFLD covers overnutrition with fatty acids, underactivity. Insulin resistance is believed to play the main role in this process. NAFLD is mostly related to visceral adiposity, metabolic syndrome and type 2 diabetes melitus. The presented work is a review of in vitro and in vivo modern studies, as well as clinical observations on molecular mechanisms leading to development and progress of NAFLD. Up till today their is no treatment od NAFLD, and this pathology is not benign--it may lead to patients' death in 10 years. The clinical approach to NAFLD is prevention of it's development. The manuscript is a review of new biochemical markers allowing for early detection of metabolic disorders leading to NAFLD development, thus to sufficient prevention of this pathology in patients.