PURPOSE: The aims were to evaluate the main risk factors (RFs) of breast cancer and to estimate the individual disease-probability from combinations of RFs in Korean female. MATERIALS AND METHODS: We conducted case-control study of 1, 687 incident cases of invasive carcinoma and 1, 238 controls during 1996~2000. A breast cancer disease-probability model was established by a general modeling process using a multivariate logistic regression model, which included the main Korean RFs and synergistic interaction-terms. RESULTS: The main Korean RFs selected were age, family history of second relatives, BMI, age at first full term pregnancy, breast-feeding, and a special test on the breasts. Two synergisms were observed between age and breast-feeding, and between special test and age at first fullterm pregnancy. The disease-probability and model are shown in Table 4, and Appendix 1. CONCLUSION: The availability of previous Western models was limited for Korean female due to the differences inhazard-rates and the characteristics of breast cancer between Asian and Western females. Due to limited basic data, i.e. incidence, hazard-rate and cancer-cohorts, the developing-probability of breast cancer for Korean females was not calculated. Therefore, the disease-probability was calculated instead. This approach might be more beneficial for Koreans, and help in the decision- making for regular screening or hospital visit-interval, counseling in breast-cancer clinics, prescribing high-risk population, and in educating for primary prevention, although it over-estimates the relative probability compared to the developing-probability and the 65% predictive validity.