Thrombosis is a common complication of Behçet disease and the pathogenic mechanism of thrombotic tendency in Behçet disease is not well known. Several platelet membrane glycoprotein gene polymorphisms have been identified as risk factors for thrombosis. This study aimed to evaluate the possible role of the GP Ia C807T/G873A polymorphism as a risk factor for thrombosis in Behçet disease. We determined the prevalence of platelet glycoprotein Ia C807T/G873A gene polymorphism in Behçet patients. Genomic DNA was obtained from 20 patients with Behçet disease and 61 controls. All individuals were of Turkish ancestry and were genotyped for the GP Ia C807T/G873A polymorphism with real-time PCR method by LightCycler system. The 807 CC, CT and TT genotypes corresponded with 873 GG, GA and AA genotypes, respectively. Complete linkage between the 807 and 873 sites was found in all samples. The 807CC(873 GG), 807CT(873GA), 807TT(873AA) genotypes found to be 45.9%, 45.9% and 8.1% in controls and 30.0%, 55.0% and 15.0% in patients with Behçet disease, respectively. The Odds Ratio for BD (OR = 1.97; 95% confidence interval (CI): 0.42-9.13) is high for the 807 TT genotype compared with controls. Thrombosis was found in 7 cases of Behçet disease group: five cases have 807CT, one case has 807TT genotype and one case has 807CC genotype. Our data indicate hat patients with BD are affected by the glycoprotein Ia gene 807TT genotypes and carrying 807T allele. The risk of thrombosis is significantly higher in patients who have 807TT and 807CT genotypes than in patients who have 807CC genotype.