Aims: To detect differences in the frequency of the known nonsynonymous CYP2W1 polymorphisms between colorectal cancer patients and healthy subjects. Materials & methods: The study group consisted of 150 colorectal patients and 263 controls. The presence of five nonsynonymous CYP2W1 polymorphisms was analyzed by novel amplification-restriction methods. Results: Two nonsynonymous SNPs causing the amino acid substitutions Val432Ile and Gln482His were monomorphic in the population study. Two nonsynonymous SNPs previously unknown in Caucasians, 1463T (rs3808348) and 173C (no rs number assigned), were detected in the population study, although these were not associated with colorectal cancer risk. Regarding the 541G/A polymorphism (rs3735684), the 541G allele (odds ratio: 2.2; 95% CI: 1.2–4.1) and the 541GG genotype (odds ratio: 2.06; 95% CI: 1.1–3.9) were associated with increased colorectal cancer risk in the population studied. Conversely, the 173C-541A-1463C haplotype (odds ratio: 0.46; 95% CI: 0.2–0.9) showed a protective odds ratio value. Conclusion: CYP2W1 variant alleles are common among Caucasian individuals and, of these, the CYP2W1 G541A (Ala181Thr) polymorphism is associated with increased colorectal cancer risk.