In the last years, type 2 diabetes mellitus (T2DM) and obesity have become a serious public health problem, behaving as epidemic diseases. There is great interest in exploring different options for the treatment of T2DM in nonmorbidly obese patients. The purpose of this study is to report parameters of glycemic control in patients with T2DM and mild obesity who underwent laparoscopic Roux-en-Y gastric bypass (RYGBP). This prospective clinical trial includes patients with T2DM with a body mass index (BMI) between 30 and 35 kg/m(2) who underwent laparoscopic RYGBP from July 2008 through October 2010. Thirty-one patients were included in the study, 15 men and 16 women, with an average age of 48.7 ± 8.6 years. The average time since onset of T2DM was 5.8 years. The average postoperative follow-up was 30.4 months. The average preoperative blood glucose and glycosylated hemoglobin were 152 ± 70 mg/dl and 7.7 ± 2.1 %, respectively. All of them were using oral hypoglycemic agents, and four patients were insulin dependent. Only one patient had a postoperative complication (hemoperitoneum). At 36 months follow-up, the average BMI decreased to 24.7 kg/m(2), all patients (31) showed improvement in their glycemic control, and 29 of them (93.6 %) met the criteria for remission of T2DM in the last control. Laparoscopic RYGBP is a safe and effective procedure that improves glycemic control in patients with T2DM and mild obesity at midterm follow-up.