OBJECTIVES: This study investigated the relationship between reproductive events during adolescence and subsequent breast cancer risk. METHODS: Logistic regression models used self-reported data from 862 case patients and 790 controls in the Carolina Breast Cancer Study. RESULTS: Miscarriage, induced abortion, and full-term pregnancy before 20 years of age were not associated with breast cancer. Among premenopausal women, breast-feeding before 20 years of age was inversely associated with disease. Oral contraceptive use before 18 years of age was positively associated with disease risk among African American women only. CONCLUSIONS: Pregnancy during adolescence does not appear to influence breast cancer risk, but breast-feeding may. A possible increased breast cancer risk among African American women who used oral contraceptives as adolescents warrants further study.