In this study, 160 cases of breast tumor which had been treated for 6 years and 6 months(from Jan. 1977 to Jun. 1983) were reviewed and summarized as follows:1) 160 cases of breast tumor(157 cases in females, and 3 cases in males) were classified as fibroadenoma. 64 cases(40%), dysplasia 42 cases(26.25%), and breast cancer. 33 cases(20.63%). 2) The abundant age groups were first and second decades in fibroadenoma, third decade in dysplasia. and fourth decade in breast cancer. 3) The most predominant complaint was palpable mass in breast(93.75%), and the duration of symptom was less than 1 year in almost patients(48.75%). 4) The right side of breast was more frequently affected than left side in patients with fibroadenoma or dysplasia(right side : 52.5%, left side : 41.25%) but in patients with breast cancer, the left side was more frequently affected. (right side : 27.27%, left side : 42.43%). 5) The most frequent site of distant metastasis was ipsilateral axllary lymph nodes(30.3%). 6) Excision was performed in most cases(69.38%), and radical mastectomy was performed in 25 cases(15.63%). 7) The size of tumor was 2cm to 5cm in most cases(51.25%).