The aim was to investigate the expression of the CXCR4 protein in five molecular subtypes of breast cancer. The authors randomly selected the breast cancer paraffin-embedded specimens of the Affiliated Third Hospital of Harbin Medical University between 2007 and 2009. Details are as follows: basal-like subtype-ER (-), PR (-), C-erbB-2 (-), CK5/6 (+), n = 36; normal breast subtype-ER (-), PR (-), C-erbB-2 (-), CK5/6(-), n = 40; luminal A subtype-ER/PR (+), C-erbB-2 (-), n = 38; luminal B subtype-ER/PR (+), C-erbB-2 (+), n = 60; C-erbB-2 (+) subtype-ER (-), PR (-), C-erbB-2 (+), n = 58. Using the immunohistochemistry method, the authors detected the expression of the CXCR4 protein in the five subtypes. The CXCR4 protein expression in the basal-like subtype was the highest, and that in the luminal A subtype was the lowest. In terms of five molecular subtypes of breast cancer, the differences in CXCR4 protein expression were significant (p < .001). In terms of C-erbB-2 expression, tumor stage, and lymph node metastasis of breast cancer, the differences in CXCR4 protein expression were significant (p < .01).