PURPOSE: The aim of this study was to assess diagnostic accuracies of ultrasonography (US) and magnetic resonance imaging (MRI) in lesions that manifest as mammographic BI-RADS 4 and 5 microcalcifications, in the setting of conjoined use of mammography, US, and MRI. ----- METHODS: Patients with mammographic BI-RADS 4 or 5 microcalcifications, without additional findings, were included in this prospective study. All patients subsequently underwent breast US and MRI. Histopathologic diagnosis, obtained by US-guided core-needle biopsy or surgical excision, served as a reference standard. Diagnostic accuracies of US and MRI were calculated, and positive predictive value for different MRI BI-RADS imaging features were determined. ----- RESULTS: The study group consisted of 113 women with 125 areas of suspicious microcalcifications. MRI reached sensitivity, specificity, positive predictive value 3 (PPV3), and negative predictive value (NPV) of 100%, 70.1%, 67.6%, and 100%, respectively. Statistically significant differences in MRI morphologic features and kinetic enhancement curves were observed between malignant and benign microcalcifications. Sensitivity, specificity, PPV3, and NPV for US were: 85.4%, 66.2%, 61.2%, and 87.9%. There was statistically significant difference in presentation of malignant and benign microcalcifications at US. ----- CONCLUSION: In the setting of conjoined use of mammography, US, and MRI, MRI can reliably exclude malignancy in suspicious microcalcifications. Thus, negative MRI findings may influence the decision to biopsy the microcalcifications.