Gastric bypass surgery has been well accepted as a novel treatment modality for type 2 diabetes mellitus (T2DM) in obese patients. Some scoring systems have been proposed for the selection of T2DM patients who are eligible for gastric bypass surgery. This study compares two scoring systems with regard to remission of T2DM after gastric bypass surgery. This retrospective cohort study included 245 patients (150 females and 95 males) who had undergone gastric bypass surgery for the treatment of T2DM with 1 year follow-up. We examined the predictive power of complete remission of two scoring systems, the DiaRem score, and the ABCD score. The DiaRem score includes the factors of age, HbA1c, medication, and insulin usage. The ABCD score includes the factors of age, BMI, C-peptide level, and duration of T2DM. The rate of remission of T2DM after gastric bypass surgery was evaluated using both scoring systems. At 1 year after surgery, the percent weight loss was 26.5 % and the mean BMI decreased from 35.7 to 26.2 kg/m2. The mean HbA1c decreased from 8.8 to 6.2 %. A significant number of patients showed improvement in glycemic control, including 130 (53.1 %) patients with complete remission (HbA1c
