Background: Breast cancer is a hormone-dependent malignancy. Sex hormone-binding globulin (SHBG) is the main transport binding protein for sex steroid hormones in plasma and regulates their accessibility to target cells. Objective: The present study aimed to assess the relationship between rs6257 and rs6258 polymorphisms in the SHBG gene with breast cancer risk. Materials and Methods: This case-control study was conducted on 100 breast cancer patients and 100 healthy control subjects. After extracting DNA from peripheral blood, Genotyping was performed using the polymerase chain reaction-restriction fragment length polymorphism method. The data were analyzed in SPSS software using the chi-square test and logistic regression to distinguish the difference between the cases and controls in terms of the distribution of allele types and genotypes. Results: The frequencies of Rs6257 were 78%, 17%, 5% in the case group and 88%, 7%, and 5% in control groups for TT, CC, and CT genotypes respectively. The rs6257 CC genotype showed about a 2.721-fold increase in breast cancer (P=0.030, OR:2.721, CI95%:1.075-6.887). This genotype was reversely associated with age, body mass index, menopausal status, and breast cancer. Nonetheless, Rs6258 had no significant correlation with breast cancer risk or other demographic factors. Conclusions: As evidenced by the obtained results, the rs6257 polymorphism may be a useful biomarker associated with breast cancer risk in Iranian women. To confirm the findings of the present study, larger studies are needed in the future.