PURPOSE: Although imaging-guided core needle breast biopsy is a minimally invasive diagnostic procedure, it is reported that patients may experience anxiety and pain. Interventions to reduce anxiety are important for high quality health services during imaging-guided core needle breast biopsy. The purpose of this study was to evaluate the effect of music intervention on anxiety and pain levels of patients undergoing ultrasound-guided core needle breast biopsy. METHODS: In a prospective randomized controlled design, patients who were referred for ultrasound-guided core needle breast biopsy were invited to the study and randomized into the intervention group who received standard care with classical music intervention before and during the biopsy procedure, and the control group who received only standard care. Both groups received local anesthesia. The Spielberger State-Trait Anxiety Inventory and the Visual Analogue Scale (VAS) were used for measuring anxiety and pain levels after the procedure. One-way multivariate analysis of variance test was used to find the effect of music intervention on patient anxiety and pain. RESULTS: There were 31 patients (48.4%) in the intervention group and 33 (51.6%) in the control group; the groups were similar in terms of sociodemographic characteristics and general (trait) anxiety levels. The patients in the music intervention group had significantly lower state anxiety score than the control group (p = 0.008) with a mean difference of 3.8 (95% CI, 1.0-6.6). The mean difference of VAS pain score was 6.0 (95% CI, 2.2-14.2), which not statistically significant between groups (p = 0.150). There was no significant correlation between the VAS and the state anxiety scale (r = 0.003, p = 0.980). CONCLUSION: Music reduced anxiety, but not pain during ultrasound-guided core needle breast biopsy. These results have implications especially for low and middle-income countries where low-cost and easily implemented interventions are needed to address patient anxiety during breast biopsy procedures.