Objective The platelet membrane glycoprotein （GP）Ⅰa/Ⅱa plays a major part as a primary colla-gen receptor in platelet function. Previous studies indicated that variations of GPⅠa/Ⅱa density and function are associated with the 807 C/T polymorphism of GPⅠa gene in American and Spanish Cau-casian populations. This study investigated the correlation between acute coronary syndrome （ACS） and 807 C/T dimorphism of GPⅠa gene in Chinese of Han ethnicity. Methods A case-control study was carried out

including 75 patients with either acute myocar-dial infarction （AMI） or unstable angina pectoris （UAP）

and 65 controls with no history of coronary heart disease

thrombogenic and hemorrhagenic diseases. Genotypes of GPⅠa were checked by polymerase chain reaction-sequence specific primers（PCR-SSP）technique. Results The frequencies of both homozygotes and heterozygotes for T807 allele（TT+TC）were significantly higher in patients with AMI than in controls（62.16% vs 33.85%

P < 0.01; odds ratio 3.21）. The prevalence of （TT+TC） genotypes was also markedly higher in patients with UAP than in controls（65.79% vs 33.85%

P < 0.005; odds ratio 3.76）. There was significant difference in the distribution of（TT+TC）genotypes not only between all patients and controls（64.00% vs 33.85%

P <0.005; odds ratio 3.47）but also between the two subgroups aged < 60 years（70.00% vs 38.24%

P <0.005; odds ratio 3.77）. However

there was no significant difference in the distribution of（TT+TC）genotypes between patients with AMI and with UAP. Platelet GPⅠa T807 allele remained significantly associated with AMI and UAP by multiple logistic regression（odds ratio 4.94）. Conclusion This study suggests a strong association between presence of GPⅠa T807 allele and ACS. T807 allele can be a marker of genetic susceptibility to ACS.