Various carcinogenic factors including estrogen metabolites play a role in malignant transformation. These metabolites are formed in part, as a result of the hydroxylation activity of cytochrome P450 (CYP) 1B1. Variant forms of this enzyme have been shown to enhance its activity, and thus, we hypothesize that single nucleotide polymorphisms of the CYP1B1 gene can be a risk factor for prostate cancer. To test this hypothesis, the genetic distribution of six different CYP1B1 polymorphisms at intron 1 (C-->T), codon 48 (C-->G), codon 119 (G-->T), codon 432 (C-->G), codon 449 (C-->T), and codon 453 (A-->G) was analyzed in 117 prostate cancer samples and 200 healthy normal subjects from a Japanese population. Results of these experiments demonstrate that the genotype at codon 119 is significantly different between prostate cancer patients and controls (P<0.001). The odds ratio of genotype T/T compared to G/G (reference) was calculated as 4.02 with a 95% confidence interval of 1.73-9.38. All other codons, except 453, showed polymorphisms but were not significantly different between cancer patients and controls. No association was found between stage and grade of cancer with any of the polymorphic sites. This is the first report that demonstrates the polymorphism at codon 119 of CYP1B1 to be associated with prostatic carcinogenesis. These results are important in understanding the role of CYP1B1 polymorphisms in the pathogenesis of prostate cancer.