Glycolytic enzyme activities of human breast cancer was studied on age, menopausal status, T, N, Stage and pathology in benign and malignant tumor. Influences on incubation with additional hormones also were studied. Mastopathy, benign tumor and breast cancer showed varied enzymic activity. High enzymic activity was observed in breast cancer tissue, but the enzymic activity was not paralleled with tumor size. Enzymic activity changed by incubation with additional hormones. Pre menopausal state, T(1), negative lymph node metastasis, Stage I tissues were elevated enzymic activity. Post menopausal state, T(3), positive lymph node metastasis, and Stage III tissues were decreased enzymic activity.