In this study, we investigated the ameliorating effects of ipragliflozin on fatty liver in patients with type 2 diabetes. The factors that influenced the amelioration of fatty liver were also examined. Analysis included data of 21 Japanese patients with type 2 diabetes obtained from our prospective observational study. After obtaining patients' informed consent, once-daily ipragliflozin (50 mg/day) was given for 16 weeks. In addition to several clinical parameters, body composition was also compared before and after 16 weeks of treatment. The extent of fatty liver was estimated using a fatty liver index (FLI). After 16 weeks, FLI significantly decreased, from 70.1 ± 19.4 to 60.3 ± 25.5 (p = 0.0009) as well as levels of fasting plasma glucose (FPG), HbA1c, body weight, visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT) and fat mass. To reveal the factors influencing the FLI changes observed on ipragliflozin treatment, correlations between changes in FLI and several other measured parameters were examined. Changes in FPG (correlation coefficient = 0.4683, p = 0.0323) and HbA1c (correlation coefficient = 0.4383, p = 0.0469) showed significant positive correlations with changes in FLI. On the other hand, no correlations of changes in FLI were observed with body weight, VAT, SAT nor fat mass. In conclusion, ipragliflozin ameliorated FLI in Japanese patients with type 2 diabetes. Improvement in FLI was associated with that of glucose intolerance.