Nonalcoholic steatohepatitis or NASH is one of the types of chronic hepatitis Although it is observed inNON-ALCOHOLIC persons, pathologically it resembles live DISEASEs that are secondary to alcohol consumption. At present, NASH is recognized as a form of NON-ALCOHOLIC FATTY LIVER DISEASE or NAFLD. New studies reveal that the prvalence of NAFLD could be much more than believed so far and most of those with this DISEASE entity are devoid of the known risk factor associated with this DISEASE. At present, the clinical characteristics of NAFLD are not fully known and as such it is considered in the differential diagnosis of most of the DISEASEs of the LIVER. On the other hand, progression to cirrhosis, and the develop ment of portal hypertension and hepatic failure in some of the patients has been established. The prevalence of NAFLD and the scarcity of information regarding the course of this DISEASE has ushered in different beliefs pertaining to diagnostic invasive investigations and specific treatment modalities. Unfortunately an exact information about the fate of these patients does not exist in Iran and the adjoining countries, and this reality in addition to the problems mentioned earlier makes a research and treatment protocol about-this DISEASE all the more necessary and evident.