Objective To evaluate the association between polymorphisms in Fas promoter region and susceptibility to breast cancer. Methods In the case-control study, we genotyped Fas-670A/G and Fas-1377A/G by PCR-RFLP in 214 patients with breast cancer and 204 healthy controls. Results were analyzed using Chi-square test. Fas gene expression wwas detected by q-RT-PCR in breast cancer. Results The distribution of Fas-670A/G genotype and allele type was significant difference between the patients and healthy controls. Subjects with GG genotype significantly increased the risk of breast cancer compared with the individuals carrying AA and AG genotype. Fas expression level in subjects with breast cancer was significantly increased compared with the healthy control. And the Fas expression in subjects with GG genotype was significantly higher than that in subjects with AA, GG genotypes. Conclusion Fas expression significantly increased in breast cancer. Fas was regulated by Fas-670A/G and significantly associated with susceptibility to breast cancer. GG genotype enhanced Fas expression and increased the risk to breast cancer.