Primary open angle glaucoma (POAG) is one of leading causes of adult blindness worldwide. To identify genetic variants associated with susceptibility to POAG, we conducted a genome-wide association study (GWAS) using 1394 cases and 6599 controls. Subsequently, we analyzed 33 single nucleotide polymorphisms (SNPs) which showed suggestive association (P < 1 × 10(-4)) by GWAS, using an additional set of 1802 cases and 7212 controls. In addition to confirmation of the association of the chromosome 9p21 locus [rs1063192, P= 5.2 × 10(-11), odds ratio (OR) = 0.75], and 14q23 (rs10483727, P = 9.49 × 10(-8), OR = 0.79) with POAG in Caucasians reported recently, we identified a suggestive-associated locus on 2q21 (rs7588567, P = 3.89 × 10(-7), OR = 0.85). For these described SNPs, minor alleles are suspected to have a protective effect from the disease. An linkage disequilibrium block containing rs10483727 includes the SIX6 gene that was implicated to have a critical role in eye development, and genes in both represented loci (SIX6 on chromosome 14q23, and CDKN2A-CDKN2B on chromosome 9p21) are known to be expressed in human ocular tissues, including the retina. Our GWAS results should contribute to better insight into the genetic basis of POAG.