breast cancer accounts for 14% of cancers in Indian women. It is reported that in every four minutes, an Indian woman is diagnosed with breast cancer. Vitamin D deficiency is assumed to be one of the risk factor for breast cancer. Objective: To study the association between vitamin D and risk of breast cancer among postmenopausal women. Methodology: This was an observational cross sectional study.About 74 females of known breast cancer and 74 healthy females were evaluated. Appropriate statistical analysis was done to find association between vitamin D deficiency and risk of Breast Cancer. Our study demonstrated that number of subjects with Vitamin D level below 20 ng /dl i.e Vitamin D deficiency from the cases, in age group 41 to 50 years are 11, in the age group of 51 to 60 years were 39, in the age group of 61 to 70 years are 19, and in the age group of more than 70 years were 5 in number. The statistical difference between vitamin D levels, in patients having breast cancer and patients not having breast cancer was highly significant (p value 0.0001), showing the strong association between decreased vitamin D level and breast cancer in postmenopausal women. Conclusion: Our study showed that vitamin D and levels were inversely associated with risk of developing breast cancer. Vitamin D helps in prevention of cancer by reducing inflammation, anti-apoptotic, and anti-proliferative property. Vitamin D supplementation are needed in premenopausal women in order to reduce the risk of breast cancer in peri and post menopausal women