Transforming growth factor β1 (TGFβ1) is suggested to be involved in the pathogenesis of and in complications with breast cancer (BC). Polymorphisms in TGFβ1 gene (TGFβ1) have been suggested by many investigators to have a role in susceptibility to BC; however, many discordant data have been reported. Considering the role of ethnic variations, we performed an association study between TGFβ1 polymorphisms and BC among Iranian women. We sequenced DNA samples of 110 BC and 110 normal control women for the exons and their adjacent intronic regions of TGFβ1 using PCR. The allele, genotype, and haplotype frequencies were calculated using PowerMarker V3.25 and R 3.0.2 softwares. Ten single nucleotide polymorphisms (SNPs) were detected. Statistical analysis on the frequency of seven most frequent SNPs, including the three coding SNPs (cSNPs) revealed no significant difference between BC and control women. Moreover, among 11 constructed haplotypes, "GTGCCGC" was significantly different between two study groups. In conclusion, we found no association between the studied SNPs of TGFβ1 and BC among Iranian women, but a possible association between "GTGCCGC" haplotype and BC was seen. However, further studies are suggested to clarify this association.