INTRODUCTION: Type 2 diabetes is the paradigm of an obesity-related disease. In most cases it exists because of the obesity and will disappear with weight loss. AIM OF THIS STUDY: To evaluate the glicemic control in obese patients after two malabsorbitive procedure, the bilio-pancreatic diversion with ad hoc stomach resection (BPD-AHS) and the bilio-pancreatic diversion with transitory gastric restriction (BPD-TGR). MATERIAL AND METHODS: The effect of weight loss following malabsorbitive procedures was studied on 38 patients operated on between the May 1999 and July 2002. Ten patients were diabetes 2 type (group A, 4 patients with oral antidiabetic therapy and 6 with insulin therapy; mean BMI: 49.4±8.2 Kg/m2 ), 18 patients were glucose intolerance (group B; mean BMI: 48,2±6,4 Kg/m2 ) and 10 patients were in normal glicemic control (group C; mean BMI: 51,2±8.3 Kg/m2 ). Five patients in group A were operated on BPD-AHS and 5 patients on BPD-TGR. Ten patients in the group B were operated on BPD-AHS and 8 patients on BPD-TGR. After 3 months from the malabsorbitive procedure group A patients stopped antidiabetic (mean BMI was: 42.3) and group B patients had normal values of glucose and insuline (mean BMI: 41.8). No significant statistically differences were observed in terms of glicemic control, BMI and Excess Weight Loss (EWL%), comparing the two malabsorbitive procedure. RESULTS: Weight loss after both BPD-AHS and BPD-TGR had a beneficial and durable effect on the fasting plasma glucose and serum insuline levels in diabetic and non-diabetic obese patients. The gastric procedure did not change the glicemic control.