Introduction: The insulin-like growth factor-1 (IGF-1) system is altered in the various vascular pathologic states, including atherosclerosis and restenosis. We investigated the genotype distribution of the polymorphisms of IGF-1 and IGF-1 receptor (IGF-1R) genes in Korean people, its association with the coronary artery disease, and its influence on the risk of restenosis after coronary artery stenting. Methods and Results: The promoter polymorphism of IGF-I gene, and the GAG1013GAA polymorphism of IGF-1R gene were determined in 150 consecutive patients treated with coronary artery stenting from January, 2003 to August, 2003. The most common allele of the promoter polymorphism in IGF-1 gene is 200-bp allele (allele frequency=0.38) in the Korean , and is different from 192-bp allele in the Caucasian (allele frequency=0.62-0.67). The GAA allele frequency (0.18) of IGF-1R polymorphism in the Korean is also different from those of the Caucasian (0.46-0.52). Polymorphisms of IGF-1 and IGF-1R genes are not associated with the number of the diseased coronary arteries and the diameter stenosis of the initial coronary angiography. Angiographic restenosis (���50% diameter stenosis at 6-month follow-up) was present in 75.0% of GAA homozygotes, 36.9% of heterozygotes, and 29.6% of GAG homozygotes (p=0.23). Rates of angiographic restenosis were 33.3%, 36.4%, and 38.2% in homozygotes of 200-bp allele, heterozygotes of 200-bp allele, and noncarriers of 200-bp allele (p=0.99). The need of target lesion revascularization (TLR) were 25.0% of GAA homozygotes, 14.8% of heterozygotes, and 16.9% of GAG homozygotes (p=0.78). Rates of TLR were 23.1%, 15.2%, and 21.1% in homozygotes of 200-bp allele, heterozygotes of 200-bp allele, and noncarriers of 200-bp allele (p=0.72). Conclusions: This is the first study for investigating the polymorphisms of IGF-1 and IGF-1R genes in the Korean. The genotype distribution of those genes in the Korean is different from those in the Caucasian. Polymorphisms of those genes are not associated with the severity of coronary artery disease and the risk of restenosis after stenting in coronary arteries.