Colorectal cancer, one million cases of diagnosis worldwide annually, is one of the most common malignant tumors and 20 % incidence caused by low penetrance susceptibility genes. Cyclin D1 (CCND1) regulating cell cycle transition may determine the susceptible individuals to genomic instability and carcinogenesis. The study aimed at examining the contribution of CCND1 genotypes to colorectal cancer risk in Taiwan. The genotypes of CCND1 A870G (rs9344) and G1722C (rs678653) were determined among 362 colorectal cancer patients and 362 age- and gender-matched cancer-free controls. Significant differences were observed between colorectal cancer and control groups in the distributions of genotypic (P = 9.71 × 10(-4)) and allelic (P = 0.0017) frequencies at CCND1 A870G. Additionally, individuals carried AG or GG genotype had 0.56- or 0.51-fold higher of odds ratios for developing colorectal cancer than the AA genotype (95 % confidence intervals = 0.40-0.78 and 0.32-0.81, respectively). Furthermore, G allele of CCND1 A870G performed a protective effects for nonsmokers and nonalcohol drinkers (P = 0.0012 and 0.0007, respectively) on colorectal cancer risk. These findings support the concept that the cell cycle regulation may play a role in colorectal cancer initiation and development and CCND1 A870G genotyping maybe a feasible technology for colorectal cancer early detection.