Background: rs1333049 polymorphism on chromosome 9p21 has been shown to affect susceptibility to coronary artery disease (CAD) in Caucasians. This study examined the association of rs1333049 with myocardial infarction (MI), angiographic severity of CAD and clinical outcome after a first acute MI in Han Chinese. Methods: rs1333049 polymorphism was genotyped in 520 patients with a first acute MI and in 560 controls. The number of angiographically documented diseased coronary arteries (luminal diameter stenosis G50%), echocardiographic left ventricular ejection fraction (LVEF), and major adverse cardiac events (MACE) during follow-up (mean, 29"15 months) were recorded. Results: Patients with MI had higher frequencies of the CC genotype (30.0% vs. 20.7%) or C allele (55.5% vs. 46.2%) compared with controls (all p-0.01). rs1333049 polymorphism was strongly associated with MI wodds ratio (OR) 1.48, 95% confidence interval (CI) 1.22-1.79x after adjusting for traditional risk factors. Although longer hospitalization stay was observed in patients with the rs1333049-C allele, this polymorphism was not related to angiographic severity of CAD, LVEF, and occurrence of MACE after MI. Conclusions: This study demonstrates an association of rs1333049 polymorphism locus on chromosome 9p21 with risk for MI, but not with post-MI prognosis in Han Chinese. Clin Chem Lab Med 2009;47:917-22.