To evaluate the relationship between abortions and risk of breast cancer, we conducted a case-control studywith 669 cases and 682 population-based controls in Jiangsu Province of China. A structured questionnaire wasused to elicit detailed information. Unconditional logistic regression analysis was performed to calculate oddsratios (ORs) and 95% confidence intervals (CIs). The results have revealed that induced abortion was related toincreased risk of breast caner. Premenopausal women who had ≥3 times of induced abortion were at increasedcrude OR (2.41, 95%CI: 1.09-5.42) and adjusted-OR (1.55, 95%CI: 1.15-5.68). Postmenopausal women with aprevious induced abortion were at increased crude OR (2.04, 95%CI: 1.48-2.81) and adjusted-OR (1.82, 95%CI:1.30-2.54), and there was a significant increase trend in OR with number of induced abortions (p for trend:0.0001). Overall, spontaneous abortion did not significantly alter the risk of breast cancer, but postmenopausalwomen who had history of spontaneous abortion were at increased OR. These results suggested that relationshipbetween breast cancer and abortions may depend on menopausal status and induced abortion may played animportant role in the development of breast cancer in Jiangsu’ women of China.