A genome-wide association study of prostate cancer in Kaiser Permanente health plan members (7,783 cases, 38,595 controls; 80.3% non-Hispanic white, 4.9% African-American, 7.0% East Asian, 7.8% Latino) revealed a new independent risk indel rs4646284 at the previously-identified locus 6q25.3 that replicated in PEGASUS (N=7,539) and MEC (N=4,679) (p=1.0×10−19, OR=1.18). Across the 6q25.3 locus, rs4646284 exhibited the strongest association with expression of SLC22A1 (p=1.3×10−23) and SLC22A3 (p=3.2×10−52). At the known 19q13.33 locus rs2659124 (p=1.3×10−13, OR=1.18) nominally replicated in PEGASUS. A risk score of 105 known risk SNPs was strongly associated with prostate cancer (p<1.0×10−8). Comparing the highest to lowest risk score deciles, the OR was 6.22 for non-Hispanic Whites, 5.82 for Latinos, 3.77 for African-Americans, and 3.38 for East Asians. In non-Hispanic whites, the 105 risk SNPs explained ~7.6% of disease heritability. The entire GWAS array explained ~33.4% of heritability, with a 4.3-fold enrichment within DNaseI hypersensitivity sites (p=0.004).