Since a serum level of alanine aminotransferase (ALT) exceeding that of aspartate aminotransferase (AST) suggests hyperalimentary fatty liver, we examined its prevalence among and the clinical characteristics of afflicted type 2 diabetic patients as well as the effect of antidiabetic agents on AST/ALT with the CoDiC-MS database prepared by the Japan Diabetes Clinical Data Management study group (JDDM). AST<ALT patients accounted for 37.5 % of 12,710 participants. These patients tended to be more frequently male, younger, and have higher values of body mass index, HbA1c, serum triglyceride, serum C peptide immunoreactivity, and HOMA-IR and lower values of FIB-4 index and rates of diabetic complications than AST≥ALT patients. Pioglitazone and sodium-glucose cotransporter 2 inhibitors remarkably reduced the ALT level, and 24.9 % of AST<ALT patients became AST≥ALT 1 year after starting these prescriptions. A multiple comparison test indicated that these patients tended to be more frequently female, older, and have a longer duration of diabetes mellitus, lower AST and HSI values and higher body mass index, γ-glutamyl transpeptidase, and FIB-4 index values than others.