Estrogens play a crucial role in the pathogenesis and progression of breast and endometrial cancer. The gene ER-alpha is polymorphic and gene variability could contribute to the level of protein biosynthesis. In the present work the distribution of genotypes and frequency of alleles of the Pvull polymorphism and Xbal polymorphism of ER-alpha gene in subjects with breast cancer were investigated.Blood samples were obtained from 103 postmenopausal women with breast cancer. The polymorphisms were determined by PCR-RFLP.The distribution of the genotypes of Pvull and Xbal polymorphism of ER-alpha in both control and patients did not differ significantly (p > 0.05) from those predicted by the Hardy-Weinberg distribution. There were no significant differences (p > 0.05) in genotype distributions and allele frequencies between subgroups assigned to histological stage.The results suggest that the Pvull polymorphism of ER-alpha gene as well as Xbal polymorphism may not be linked with appearance and development of breast cancer.