Objective：To investigate the expression and correlation of cyclooxygenase-2 （COX-2） and c-erbB-2 in human breast cancer. Methods： The expressions of COX-2 and c-erbB-2 in 48 breast cancer patients with breast cancer were detected with immunohistochemistry examination and was analyzed. The relationship between their expression and the clinicopathologic characters of breast cancer was also analyzed. Results： The positive rate of COX-2 was 60.4% （29/48） in these patients; the expression was higher in patients with tumor size larger than 2 cm, lymph node metastasis, and negative expression of ER or PR, but was not related with the ages, the pathologic types and the TNM stages. Expression of c-erbB-2 was identified in 39.6% （19/48） of these patients; the expression was significantly higher in patients with lymph node metastasis or negative expression of ER and PR, but was not related width the ages, the sizes and the pathologic types. COX-2 was positive in 84.2% （16/19） of patients positive of c-erbB-2 and in 44. 8 % （13/29） of patients negative of c-erbB-2, with significant difference found between the 2 figures（P=0. 006）. Conclusion： The high expression of COX-2 in breast cancer is related to the expression of c- erbB-2, suggesting that they may regulate each other and jointly contribute to the tumorigenesis and progression of breast cancer.