Fatty Liver (hepatosteatosis) means to contain fat at least 5% more of its own weight of the liver. This condition clinically may encounter in two ways: alcohol-induced fatty liver and more frequently as nonalcoholic fatty liver. Nonalcoholic fatty liver disease can be seen in all age groups and ethnic groups. In general population, the prevalence is around 14-30%. Basically, every case accompanied by insulin resistance is a risk factor for nonalcoholic hepatosteatosis. Fatty liver is more prevalent in men than women and it is reported that independent of body weight, it is related with the waist / hip ratio. In hepatosteatosis most cases are asymptomatic. Weakness, fatigue, pain in right upper quadrant of the abdomen and a feeling of fullness can accompany. Hepatomegaly during a routine physical examination and a mild increase in ALT-AST (1-4 times) can be found. As Ultrasonography is inexpensive, noninvasive and easily accessible, it is the most frequently used method in the diagnosis of hepatosteatosis. Liver biopsy is the gold standard for diagnosis, also despite being applied in selected patients it is the most reliable diagnostic method for hepatosteatosis for evaluating etiology and grading. The accurate differential diagnosis of steatosis and steatohepatitis can only be done with biopsy. In hepatosteatosis, secondary reasons such as Hepatitis C infection, metabolic disorders, some certain medications and eating disorders should not be overlooked in the differential diagnosis and the etiology. First of all etiology must be identified then the treatment should be determined later regarding the etiologic factor. Associated metabolic diseases such as diabetes, hyperlipidemia should be regarded; exercise, weight loss and pharmacotherapy methods should be considered. Liver protective agents such as antioxidants must be taken into account for treatment. Among all nonalcoholic hepatosteatosis cases 5% of them develop cirrhosis in an average of 7 years and 1.7% have been reported to result in death.