BackgroundMetabolic dysfunction-associated fatty liver disease (MAFLD) represents a new classification system for fatty liver disease. In this study, we investigated the clinical characteristics of patients with MAFLD-hepatocellular carcinoma (HCC) in comparison with those with nonalcoholic fatty liver disease (NAFLD) and considered the validity and challenges of the new criteria.MethodsThis study included 237 untreated non-B, non-C HCC patients with hepatic steatosis. We examined the profile and laboratory findings of patients with MAFLD-HCC and NAFLD-HCC. We also classified MAFLD-HCC patients according to the factors on which the diagnosis was based and compared their clinical characteristics.ResultsA total of 222 (94%) and 101 (43%) patients were diagnosed with MAFLD and NAFLD, respectively. MAFLD-HCC patients were more likely to be male than NAFLD-HCC, but there were no significant differences in metabolic indices, noninvasive liver fibrosis score or HCC status. In a study of MAFLD-HCC patients by diagnostic factor, those with overweight only were younger and had advanced liver fibrosis histologically, and when limited to patients younger than 70 years, the majority were overweight. Redefinition of overweight as BMI ≥ 25 reduced the number of MAFLD-HCC patients by only 5, from 222 to 217.ConclusionsMAFLD accounted for the majority of non-B, non-C HCC cases with hepatic steatosis. Examination of additional cases and revision of the detailed criteria is needed so that it can be used to efficiently select patients with fatty liver who are at high risk of developing HCC.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12876-023-02851-y.