Breast cancer is the most common cancer among females worldwide and it is responsible for 370,000 deaths annually. The incidence rate of breast cancer is increasing while the mortality rate is decreasing. The burden of this cancer is rising with increasing recognition of many risk factors. This study evaluated lifestyle and reproductive risk factors and their relationship with breast cancer risk in the Sultanate of Oman. It also investigated the role of IGF1 CA repeats gene polymorphism with the risk of breast cancer among Omani women. A case control study was conducted using 174 Omani females with breast cancer either newly diagnosed or old cases from SQUH and Royal Hospital, and 149 Omani female without any history of any type of cancer which served as controls. A pretested Questionnaire was used to assess the risk factors and blood samples were collected to investigate the IGF1 CA repeats polymorphism. Using univariate and multivariate logistic regression analysis method; Age, Occupation, Family Income, Family History of breast cancer, use of contraceptives and duration of contraceptives use appeared to be associated with the development of breast cancer among Omani women. Breast cancer among Omani females presents at advanced stage and at younger age as compared to Western countries. In case of IGF1 CA repeats, CA 19 was the most frequent genotype among both cases and controls followed by CA 18. The overall distribution of CA genotypes was significantly different between cases and controls (P value = 0.022) and was observed among premenopausal women (P value = 0.003) while among postmenopausal the distribution was not significantly different (P value = 0.429). Odds Ratios and 95% CI for IGF1 genotype groups showed that there was no significant association between breast cancer and CA 19 either among pre or postmenopausal women even after adjusting the strongest risk factors of breast cancer. However, there was a significant association between breast cancer and both progesterone receptor status and type of the cancer. In conclusion, even though the incidence of breast cancer in Oman is low. It is increasing. More concern should be taken in increasing the awareness of breast cancer especially the most significant risk factors among Omani women.