\[Abstract\]ObjectiveTo compare the efficacies of Roux-en-Y gastric bypass (RYGBP) and billiopancreatic diversion(BPD) in treatment of rats with non-obese type 2 diabetes mellitus. MethodsTotally 48 Goto-Kakizaki rats were randomized to undergo one of the following procedures: Roux-en-Y gastric bypass(n=16), biliopancreatic diversion(n=16), and sham operation (n=16). The fasting blood glucose and fasting insulin were determined before and 1, 3, 6, 9, 12, and 24 weeks after operation; the hematoglobin A1c (HbA1c) levels were determined before and 6, 12, and 24 weeks after operation and the insulin resistance index (HOMA-IR) was calculated. The mortality and complications were observed in each group. ResultsThe fasting blood glucose levels were significantly decreased during 1-24 weeks after operation in both Roux-en-Y group and biliopancreatic diversion group(P<0.01 or P<0.05); the HbA1c levels were also decreased 12 and 24 weeks after operation (P<0.01); and the above parameters were not significantly changed in the sham operation group. The fasting insulin levels were not significantly different between the 3 groups. In RYGBP group and the BPD group, the HOMA-IR indices decreased significantly 1-24 weeks after operation compared with those before operation (P<0.05), and those in the BPD group were significantly lower than those in the RYGBP group at all time points (P<0.05). The mortality was 6% in the RYGBP group and 50% in the BPD group. The complication rate and mortality in the BPD group were significantly higher than those in the RYGBP group (P<0.05). ConclusionRYGBP and BPD have similar efficacies in treatment of rats with non-obese type 2 diabetes mellitus, and BPD can lead to higher incidences of complications and mortalities than RYGBP.