Background: It has become important in the preoperative work up of breast cancer patients to analyze estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and Ki67 in core needle biopsy (CNB). These factors reflect response or resistance to endocrine therapy, chemotherapy and target therapy. Furthermore, factors help to select adjuvant or neoadjuvant treatment. For accuracy of ER, PR, HER2, and Ki67 in CNB, we compared the results of CNB and those of surgical specimen. Methods: We retrospectively reviewed data from 161 breast cancer patients whose ER, PR, HER2, and Ki67 were analyzed in both CNB and surgical specimen between 2013 and 2014. Patients who received neoadjuvant chemotherapy were exclued in this study. ER, PR, and Ki67 were determined by immunohistochemistry (IHC) and reported as percentage. The cut-off point for ER and PR was 1%, and for Ki67 was 14%. HER2 was determined by IHC and/or fluorescence in situ hybridization (FISH). HER2 positive was defined as IHC 3+ or FISH (+). Results: The mean percentage in CNB and surgical specimen were 59.4% and 58.9% for ER, 46.1% and 44.6% for PR, and 24.0% and 26.8% for Ki67. The expression difference between CNB and surgical specimen for ER and PR were not statistically significant (P = 0.681 and P = 0.455, respectively). However, Ki67 level in surgical specimen was higher than that in CNB with statisticall significant (P = 0.038). According to cut off value, ER, PR, HER2, and Ki67 were divided into positive and negative. The sensitivity of ER, PR, HER2 and Ki67 in CNB were 92.4%, 96.3%, 100%, and 81.7%, respectively. The specificity of ER, PR, HER2 and Ki67 in CNB were 85.7%, 81.7%, 97.9%, and 91.2%, respectively. The positive predictive value(PPV) and negative predictive value(NPV) of CNB were 94.8% and 80.0% for ER, 91.2% and 91.7% for PR, 93.5% and 100% for HER2, and 94.5% and 72.9% for Ki67, respectively. Conclusions: The ER, PR, HER2 in CNB were generally well correlated with those in surgical specimen. Especially, HER2 status of CNB was the most accurate factor compared with surgical specimen. When we consider neoadjuvant HER2-targeted agents, HER2 status based on CNB can be very useful and reliable result. Ki67 level in CNB was slightly lower than that in surgical specimen.