Non-alcoholic fatty liver disease (NAFLD) refers to the presence of hepatic steatosis (accumulation of fat in the liver to over 5% of its weight) in the absence of secondary causes of fat accumulation in the liver such as excessive alcohol use. NAFLD is divided into two types: non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH). Therefore, in this clinical guideline, we sought to determine general and important policies for this disease and modify its managment approaches. We adapted this guideline for the management of NAFLD in Isfahan Province. This guideline was developed by clinical appraisal and review of the evidence, available clinical guidelines, and in consultation with members of the Isfahan Chamber of the Iranian Association of Gastroenterology and Hepatology. Biopsy is recommended as the most reliable method (gold standard) to diagnose steatohepatitis and fibrosis in patients with NAFLD. NAFLD fibrosis score (NFS) and fibrosis-4 (FIB-4) are recommended as the test with the highest predictive value for advanced fibrosis in patients with NAFLD compared to other serologic tests. Among the noninvasive methods used to assess liver fibrosis, transient elastography (TE) is preferable to other methods.