Background: Matrix metalloproteinases-2 and -9 play important roles in the development of breast cancer by hydrolyzing the extracellular matrix. Since −1306C/T and −1562C/T polymorphisms are located at the promoter regions of the matrix metalloproteinase- 2 and -9 genes, respectively, C to T substitution may affect promoter activity and impact the rate of extracellular matrix degradation and cancerous cell proliferation. Therefore, we aimed to determine the genotype and allele frequencies of these polymorphisms in Iranian healthy women and women with breast cancer. We have also examined the correlation of genotypes with clinicopathological parameters such as tumor type, tumor size, and metastasis to lymph nodes.Methods: This case-control study enrolled 200 women with breast cancer and 200 age-matched healthy women. DNA was extracted, and we determined the genotype and allele frequencies of −1306C/T matrix metalloproteinase-2 and −1562C/T matrix metalloproteinase-9 polymorphisms by the polymerase chain reaction-restriction fragment length polymorphism method. Additionally, tumor size (20 mm), tumor type (ductal/non-ductal), and metastasis (yes/no) were determined.Results: Genotype and allele frequencies of the −1306C/T matrix metalloproteinase- 2 polymorphism showed no significant association with the occurrence of breast cancer. Genotype and allele distribution differed in the −1562C/T matrix metalloproteinase- 9 polymorphism and indicated a 4.83-fold increase in the risk of breast cancer for T allele carriers. There was no likelihood of any interaction found between the two polymorphisms and susceptibility to breast cancer. In addition, the −1562C/T matrix metalloproteinase-9 T allele showed an association with metastasis to lymph nodes but we observed no association between the −1306C/T matrix metalloproteinase- 2 polymorphism and clinicopathological features.Conclusion: The ‒1562C/T matrix metalloproteinase-9 polymorphism is involved in the pathogenesis of breast cancer in Iranian women. The T allele may increase the risk of disease.