Background.Although prothrombotic disorders (PTD) are known to increase the risk of graft failure in kidney transplantation only, there are no data on PTD in simultaneous pancreas and kidney transplantation (SPK).Methods.Forty-seven SPK performed between September 2000 and July 2002 underwent routine screening for PTD. Data were retrospectively analyzed in view of complications (relaparotomy, graft thrombosis, pancreatitis, rejection) and graft function (HbA1c, serum creatinine) 3 months posttransplantation.Results.Twenty-five of forty-seven (53.2%) patients had 30 PTDs. Homozygous mutations of the MTHFR gene (C677T) were found in six, factor-V Leiden mutation (homo- or heterozygous G1691A) in seven, and prothrombin mutation (20210A) in one patient (group 1). Group 2 consists of deficiencies of protein C (n=1), of protein S (n=12), of antithrombin (n=1), and antiphospholipid syndromes (n=2). Overall, PTD had no influence on graft thrombosis (P=0.36) or rejection (P=0.56). In patients with homozygous mutations, relaparotomies were more often necessary than in patients without mutations (42.9% vs. 11.8%,P=0.046). In group 1, there was a trend toward a higher incidence of graft pancreatitis than in patients without mutations (38.5% vs. 14.7%,P=0.075). Three months posttransplantation, HbA1c was 6.0% in patients with and 5.5% in patients without PTD (P=0.023). With regard to serum creatinine, no significant differences were observed.Conclusion.PTD are frequent in type-1 diabetics receiving SPK and may have a role in relaparotomies, graft pancreatitis, and pancreas graft function.