Aim: Nonalcoholic steatohepatitis (NASH) is a liver disease characterized by lipid accumulation and inflammation. Here, we aimed to evaluate plasma IL-1Ra as a marker for NASH and to determine whether diagnosis of NASH can be further improved by adding IL-1Ra measurements. Materials & methods: Therefore, plasma concentrations of IL-1Ra were measured from 146 subjects of a biopsy-proven NASH cohort with matched controls. Results: NASH patients had higher levels of plasma IL-1Ra compared with patients with steatosis or healthy controls. Conclusion: Our data confirm that IL-1Ra can be a useful tool in the diagnosis of hepatic inflammation and suggest that measuring plasma IL-1Ra levels in addition to ALT will improve the diagnosis for NASH at all stages of the disease.