Abstract: Objective 　To study the expression and significance of nuclear t ranscription factor-κB (NF-κB) and tumor suppressor gene p53 protein in breast cancer. Methods 　Immunohistochemical staining was used to detect the expression of NF-κB p65 and p53 protein in 58 cases of breast cancer and 20 cases of proliferative breast disease. Results 　The expressive degree of NF-κB in breast cancer was significantly higher than in proliferative breast disease. The positive intensities of NF-κB was associated with histologic grading and axillary lymph node metastasis, but was not associated with age, tumor size, and histological type. The expressive degree of p53 is significantly higher than in proliferative breast disease. The positive intensities of p53 were associated with histologic grading, but were not associated with age, tumor size, histological type and axillary lymph node metastasis. The expression of NF-κB and p53 protein were significantly positive correlated in breast carcinoma ( r = 0. 302, P < 0. 05) . Conclusion 　It is suggested that the abnormal expression of NF-κB and p53 are associated with the pathogenesis and development of breast cancer.