Breast cancer is a major cause of death in women worldwide. Mammary tissue expressing xenobioticmetabolizing enzymes metabolically activate or detoxify potential genotoxic breast carcinogens. Deregulationof these xenobiotic metabolizing enzymes is considered to be a major contributory factor to breast cancer. Thepresent study is focused on the expression of the xenobiotic metabolizing gene, CYP1A1, in breast cancer and itspossible relationships with different risk factors. Twenty five tumors and twenty five control breast tissue sampleswere collected from patients undergoing planned surgery or biopsy from different hospitals. Semi-quantitativereverse transcriptase polymerase chain reaction (RT-PCR) and western-blotting were used to investigate theexpression of CYP1A1 in breast cancer control and disease samples. mRNA expression of CYP1A1 was downregulatedin 40% of breast tumor samples. Down-regulation was also observed at the protein level. Significnatrelations were noted with marital status and tumour grade but not histopathological type. In conclusion, CYP1A1protein expression was markedly reduced in tumor breast tissues samples as compared to paired control tissuesamples.