Abstract: Objective To study the effect of neoadjuvant chemotherapy on estrogen receptor (ER), progesterone receptor (PR), and HER-2 expression in patients with breast cancer. Methods From 59 breast cancer patients treated with neoadjuvant chemotherapy and 33 without neoadjuvant therapy (control), core biopsy samples before the chemotherapy or surgery and surgical specimens were obtained for assay of ER, PR, and HER-2 expression. Results Quantitative alteration of ER expression occurred in 37.29% (22/59) of the patients after neoadjuvant chemotherapy and in 15.15% (5/33) of the control patients, showing statistically significant difference between the two groups(P<0.05), but the changes in ER expression status (conver-sion between positivity/negativity ratio) exhibited no significant difference. After the surgery, quantitative changes in PR expression was noted in 23.73% (14/59) of patients with neoadjuvant chemotherapy, without significant difference from those in the control group or changes in the expression status. Similarly, the changes in HER-2 expression seen in 13.56% (8/59) of the patients with chemotherapy was also comparable with the control group, without significant changes in the expression status. Conclusions Significant changes occur in ER receptor expression after neoadjuvant chemotherapy in patients with breast cancer, but such changes do not affect the ER status. Neoadjuvant chemotherapy has no significant effects on PR and HER-2 expression in breast cancer patients.