Background: One of the most frequent causes of chronic liver disease globally is non-alcoholic fatty liver disease (NAFLD). It is believed that NAFLD is the hepatic expression of metabolic syndrome. Historically, NAFLD was thought to be a rather benign liver condition. Hepatocellular carcinoma, cirrhosis, and liver fibrosis can develop in some NAFLD patients. Consequently, it is crucial from a clinical standpoint to accurately diagnose and stage NAFLD patients. Objective: This study aimed to evaluate the performance of pro collagen III as a NASH-Fibrosis biomarker within the optimum diagnostic context of usage in comparison with FIB-4. Patients and Methods: This study was a case-control study that was conducted at Gastroenterology and Hepatology Outpatient Clinic at Damas Centre for Liver and GIT. This study was performed on 56 Egyptian patients who were ≥ 18 years of age and are overweight with Body Mass Index ≥ 25 and diagnosed with NAFLD by US. They were divided into 2 groups: Group 1 included 28 healthy individuals diagnosed with NAFLD by US without any evidence of hepatitis and group II that included 28 patients with NASH diagnosed by elevated liver enzymes. Results: Patients with non-alcoholic steatohepatitis (NASH) have relatively low platelet count in comparison with NAFLD patients. Patients with NASH had Higher AST & ALT levels than NAFLD patients. FIB-4 was higher in NASH group than NAFLD group. Pro collagen III level was higher in patients with NASH than patients with NAFLD. Pro collagen III was a significant discriminator of NAFLD & NASH. Pro collagen III correlates with the grades of histological steatohepatitis, and stage of fibrosis. Pro collagen III can diagnose steatohepatitis at cut-off 9.57 with sensitivity & specificity was 92.9% & 92.9% respectively. Conclusion: Pro collagen III is a sensitive biomarker to discriminate between NAFLD & NASH. Pro collagen III level correlate positively with BMI, AST & ALT. Pro collagen III level correlate with grades of histological steatohepatitis and grades of fibrosis.