Background Roux-en-Y gastric bypass (RGB) has been endorsed by the “First World Congress on International Therapies for Type 2 diabetes” as a possible therapeutic option in patients with type 2 diabetes with a body mass index (BMI) of less than 35 kg/m 2 . In the present study, we assessed the improvement in clinical indicators associated with laparoscopic Roux-en-Y gastric bypass (LRYGB) in patients with non-obese type 2 diabetes mellitus (T2DM). Methods LRYGB was performed in 30 T2DM patients with a BMI <35 kg/m 2 . The patients were followed up for 1 year. Pre- and postoperative changes in BMI, waist circumference, and biochemical indicators including fasting plasma glucose and glycosylated hemoglobin were recorded. Results Significant reduction in glycosylated hemoglobin from 8.02 ± 1.77 to 5.59 ± 1.02 % ( p  < 0.05) at 12 months was noted. Diabetes was completely resolved in nine cases, resulting in discontinuation of diabetes-related medication. No significant surgical complications occurred. Conclusions LRYGB is beneficial for non-obese T2DM patients in China.