Simultaneous pancreas-kidney (SPK) transplantation is considered a valid therapeutic option for patient with type I diabetes mellitus and end-stage diabetic nephropathy. This study was performed to determine whether the technique of pancreas venous drainage affects patient survival as well as graft survival and function. From October 1996 to April 1999 34 uremic patients with type I diabetes mellitus were randomly assigned to two groups: the first group (SV group = 17) received SPK transplantation with systemic venous drainage, and the second group (PV group = 17) received pancreas allograft with portal drainage. A Roux-en-Y loop was performed in all the patients. Patient follow-up included clinical course and metabolic studies. At 1 yr, patient survival rates were 88.2% in the SV group and 94.1% in the PV group while graft survival rate was 76.4% in both groups. Several surgical complications were attributed to the enteric drainage without any graft failure in both groups. One venous thrombosis occurred in each group. No significant differences have been evidenced in kidney and pancreas function. The preliminary results of this randomized trial did not evidence any significant differences between portal and systemic venous drainage of pancreas allograft.