The potential involvement of N-acetyltransferase 1 (NAT1) genetic polymorphisms in prostate cancer (PCa) patients was analyzed in 101 patients with PCa and 97 controls with no incidental malignancy. Identification of NAT1*10, the variant allele associated with the rapid acetylator phenotype was by allele-specific polymerase chain reaction (PCR). When the NAT1*10 heterozygote and other genotypes without NAT1*10 allele were considered as low risk genotypes, NAT1*10/NAT1*10 had a significantly higher risk of PCa (OR = 2.4, 95% CI; 1.0-5.6). If our preliminary results can be confirmed in a larger population, it may be a useful marker for PCa risk.