Objective: Breast cancer is a common malignancy in women in both western countries and in India and is still one of the leading causes of death in women. The relationship between breast cancer and thyroid diseases is controversial. The aim of the present study is to evaluate the incidence of auto immune and non auto immune thyroid diseases in breast cancer patientsMethods: The role of thyroid hormones status in breast cancer patients was estimated by measuring serum free Triiodothyronine, serum free Tetraiodothyronine, serum Thyroid Stimulating hormone levels and the role of antibodies by measuring anti thyroid peroxidase (anti-TPO) antibodies , anti thyroglobulin antibodies(anti-Tg) in blood. For this, 100 cases of breast cancer patients were included. The findings were compared with 75 age matched healthy females. Results: A significant increase in the levels of Thyroid Stimulating Hormone and anti-Thyroid peroxidase antibodies were observed in the cases as compared to controls. There were no significant differences in the levels of free Triiodothyronine(FT3), free Tetraiodothyronine(FT4), and anti thyroglobulin antibodies(anti-Tg). Conclusion: Our results indicate increased incidence of auto immune and non auto immune thyroid diseases in breast cancer patients when compared to controls.