The terminal elimination half-life (t1/2) of empagliflozin is 13.1 hours. Accordingly, we hypothesized that the administration of empagliflozin every other day might improve glycemic control in patients with type 2 diabetes mellitus, not being inferior to the therapy every day. We investigated the clinical effects and safety of the addition of empagliflozin every day or every other day to type 2 diabetic patients with a poor control in glycemia. Thirteen Japanese patients diagnosed as type 2 diabetes mellitus recruited to this study. Subjects were divided into two groups; one was treatment with 10 mg of empagliflozin every day (Group A), the other was 10 mg of empagliflozin every other day (Group B). The comparable study of multiple clinical indexes between the 2 groups was made before and 8, 16, and 24 weeks after the treatment. After the treatment for 24 weeks, the HbA1c level was decreased both in group A (from 7.5%±1.1% to 6.5%±0.8%) and in group B (from 7.6%±0.8% to 7.2%±0.5%). This pilot trial suggested the possibility of 10-mg every other day administration with empagliflozin for Japanese patients with type 2 diabetes mellitus. J. Med. Invest. 64: 50-57, February, 2017