Introduction: Breast cancer is the most common cancer in women, comprising a third of all cancers in women. Used by millions of women on daily basis, contraceptives are a potential risk in incidence of cancer. This study aimed to investigate the relationship between incidence of cancer and use of contraceptive pills. Materials and methods:This is a retrospective analytical control-case study conducted on 235 breast cancer patients and 235 women in the control group. Data collection tools included a set of questions in the form of interviews and patients' medical records. Data were analyzed using statistical tests: t-test, Chi-square, Fisher, and Pearson Correlation Coefficient. Results:The results indicated a significant relationship between breast cancer and history of contraceptive use, and also age at onset of use. However, the relationship between breast cancer and age at discontinuation of use, pattern of use, or interval since last use was insignificant. Discussion and conclusion:The study results showed a significant relationship between breast cancer and contraceptive use (OR=2.11). Contraceptive use doubled the incidence of breast cancer. Findings of this study can be used as a guide for care and screening planning for contraceptive users.