The present study was undertaken to examine the frequencies of GSTM1 (Null/Present), GSTP1 (Ile105Val) and p53 (Arg72Pro) genotypes and their relations to breast cancer susceptibility in South Indian women. This case - control study involved 250 consecutive breast cancer cases and 500 healthy controls matched in five-year age categories in the ratio of 1:2. Genotyping was performed by PCR for GSTM1, Real-Time Allelic discrimination assay for GSTP1 and PCR-CTPP for p53. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using conditional logistic regression after adjusting for the known risk factors for breast cancer. The frequencies for the GSTM1 Null genotype were 26% in the cases and 22% in the controls; for GSTP1 Ile/Ile, Ile/Val, Val/Val the frequencies were 46.6%, 41.9% and 11.5%, respectively, in cases and 46.0%, 43.8% and 10.2% in controls; for p53 Arg/Arg, Arg/Pro & Pro/Pro the frequencies were 26.4%, 50.0% and 23.6% in cases and 27.0%, 44.8% and 28.2% in controls. A nonsignificant elevation in breast cancer risk was observed among women who had the GSTM1 Null genotype (OR=1.24; 95% CI=0.83-1.84), the p53 Arg/Arg genotype (OR=1.28; 95% CI=0.81-2.03) and the Pro/Arg genotype (OR=1.49; 95% CI=0.99-2.25), and the GSTP1 Val/Val genotype (OR=1.1; 95% CI=0.64-1.91).