Breast cancer is initiated by exposure to endogenous and exogenous estrogens. A case-control (n=250-500)study was undertaken to investigate the role of Single Nucleotide Polymorphisms (SNP’s) in CYP17 (T-34C),CYP19 (Trp39Arg) and FGFR2(C-906T). Genotyping was done using the Taqman allelic discrimination assayfor CYP17 (T-34C) and FGFR2 (T-906C) and PCR-CTPP for CYP19 (Trp39Arg). There was a significantprotective association of the (TT/CC) genotype of the CYP17 gene against the risk of developing breast cancer(OR=0.68, 95% CI: 0.49-0.96), which was more significant in postmenopausal women (OR=0.56, 95% CI: 0.35-0.89) (p=0.015). CYP19 (Trp39Arg) is a rare polymorphism and all the cases were homozygous for the wild typeTrp allele (100%); this was also the case for 99.2% of the controls. We were unable to detect any variant form ofthe CYP19 gene in south Indian women. There was no significant association between the risk of breast cancerand FGFR2 (C-906T). These results suggest that the CYP17 TT/CC genotype is associated with decreased riskfor breast cancer, especially in post menopausal women.