After stratification by accumulative smoking amount of 500 cigarettes per year, the risk for CRC increased significantly in the subjects with heavy smoking history (>500 cigarettes per year) and XRCC1 194Arg allele (194 Arg/Trp or 194Arg/Arg) in comparison with the subjects who were 194Trp/Trp genotype and never smoked (OR = 2.91, 95 % CI 1.35–6.24). This evidence concerns the gene XRCC1 and colorectal carcinoma.