BACKGROUND AND PURPOSE: An accurate diagnosis of a parotid gland mass is essential for adequate management. We determined the clinical efficacy of USCNB in diagnosing parotid gland masses by using cutting needles of different bores. METHODS: We reviewed records for 40 benign and 13 malignant parotid lesions. USCNB was performed by using 14-20-gauge needles (mean, 16.6 gauge) with one to five (mean, 2.43) passes and a 15-mm throw or specimen notch. Final diagnoses were established on the basis of surgicopathologic results in 31 cases, and on the basis of histopathologic analysis of biopsy specimens, clinical data, and/or imaging studies in 22, with a follow-up of 12.2-77.5 months (mean, 33.6 months). RESULTS: Compared with surgicopathology, USCNB had a sensitivity of 83%, a specificity of 100%, and an accuracy of 97% in providing specific tissue diagnoses and in differentiating malignant from benign masses. Its positive and negative predictive values were 100% and 96%, respectively, in diagnosing malignancy. One patient (2%) had a local hematoma without sequela after surgical removal of a Warthin tumor. Core biopsy results were completely concordant with surgical findings in 30 (97%) of 31 cases. CONCLUSION: USCNB is a safe and efficient diagnostic procedure with an accuracy of 97% in the pathologic diagnosis of parotid masses. It can be performed in an outpatient clinic and enables specific tissue diagnosis to obviate intraoperative frozen biopsy and unnecessary surgery. An 18-gauge needle is sufficient for accurate and specific tissue diagnosis of parotid masses. Copyright American Society of Neuroradiology