Objective: Hormone receptor (HR) and Her2/neu expressions may change following neoadjuvant chemotherapy. The clinical significance of this receptor alteration is unclear. We retrospectively investigated the frequency of HR and Her2/neu status change in response to neoadjuvant chemotherapy. Material and Methods: Medical records of 49 patients with locally advanced breast cancer treated with anthracycline- and/or taxane-based neoadjuvant chemotherapy were retrospectively evaluated. The median age at diagnosis was 53 years (range, 27-79). All patients were operated within 3-4 weeks of the last cycle of chemotherapy. We also analyzed the relation of tumor marker alterations with patient outcome. Results: Alterations in hormonal receptor and Her2/neu protein expression were observed in 16 (32.6%) of the 49 patients. There was no statistically significant difference in HR expressions before and after neoadjuvant chemotherapy (p=NS). In addition, two (4%) patients with positive Her2/neu became Her2/neu negative after neoadjuvant chemotherapy. Twelve (24%) patients with negative estrogen and progesteron receptor expressions were converted to positive after neoadjuvant chemotherapy. There was no effect of HR alterations on patient outcome. Conclusion: HR and Her2/neu expression alterations are not infrequent in response to neoadjuvant chemotherapy. Tumor marker status determination in the final surgical specimen is recommended.