Background and study aim: Non-alcoholic fatty liver disease (NAFLD) is a state defined by extreme fat accumulation in the form of triglycerides (steatosis) in the liver. A subgroup of NAFLD patients characterized by injury to the hepatocytes and inflammation in addition to excessive fat, the latter condition, nominated non-alcoholic steatohepatitis (NASH). The work aimed to evaluate the role of serum resistin level as a diagnostic marker in patients with non-alcoholic steatohepatitis who were admitted to the Tropical Medicine and Internal Medicine departments, Faculty of Medicine, Zagazig University (inpatient and outpatient). Patients and Methods: This study was performed on 38 patients between April2017 to May 2018.They were classified into two groups; control group included19 non-obese apparently healthy individuals, 11 males and 8 females with average age of 43.2 year and average body mass index of 23.46 Kg/m2 and patients’ group included19 patients with NASH, 13 males and 6 females with average age of 44 year and average body mass index of 32.71 Kg/m2. They had bright fatty liver on ultrasonographic examination and raised ALT and AST and liver biopsy confirmed the diagnosis of NASH. Clinical assessment, laboratory evaluation, pelvi-abdominal ultrasound, and serum resistin were done for all participants. Results: In this study: Cut off level of serum resistin was >3.7 ng/ml and there was a significant difference as regard serum resistin in NASH group in comparison with control group. Conclusion: Serum resistin level was significantly higher among NASH group in comparison to the control group. Serum resistin level may be a good diagnostic marker for patients with NASH.