Abstract: Objective :To test the expression of apoptosis regulation gene Bcl-2 and Bad in the benign and malignant breast lesion, and to explore the role of they in the growth and development of breast cancer. Methods : By immunohistochemical methed, the expression of Bcl-2 and Bad gene were observed in eight cases with normal breast tissue, 19 breast hyperplasia and 20 breast atypical, as well as 48 with breast cancer in situs. Eight cases of normal breast tissue were used as the controls. Results :The Bcl-2 gene was 100L positive expression in the 8 cases of normal breast tissues and 19 with breast hypreplasia, and was 85.0L in breast atypical, and was 58.3% in breast cancer. A statistical signification was found between the positive rate of atypical cancer and of breast cancer (χ²=4.48 P<0.05 ). The positive rate of Bad oncoprotein was of lower tendency compared to Bcl-2 of all groups: 87.5% in normal, 84.2% in hyperplasia, 55.0% in atypical, 47.9% in breast cancer, respestively. There was a significant difference between positive rate of Bcl-2 and of bad in each group. (χ²=23.05 P<0.001,χ²=11.29 P<0.01). In the breast cancer group the positive rate of Bcl-2 and Bad oncoprotein was decreasd with a descent in differentiation of tumor. Conclusions : Bcl-2 and Bad oncoprotein may play a role in growth and development of cancer and may relate to the apoptosis regulation of breast cancer.