A common 870G > A polymorphism in the gene for cyclin D1, CCND1, has been linked to alternative splicing and cancer susceptibility. To analyze its role for breast cancer, we determined the CCND1 genotype in 500 breast cancer patients and 500 controls. CCND1 genotype frequencies were similar among patients and controls. The CCND1 genotype was furthermore not associated with tumor characteristics. We conclude that the CCND1 870G > A polymorphism is not associated with breast cancer.