A preoperative diagnosis of a parotid carcinoma is more difficult than other head and neck carcinomas, especially the histological type. Therapy should be carried out according to each histological type because each has different tumor activity. We reviewed 32 cases of previously untreated carcinomas arising in the parotid gland over a 10-year period and investigated the accuracy of the preoperative diagnosis and the first operation. Fine-needle aspiration biopsy (FNA) of the salivary gland is an accepted, sensitive and specific technique in diagnosing tumors. FNA was performed for all patients with parotid carcinomas, and the FNA findings were compared with the final pathologic diagnosis of the surgically resected specimen. In 32 cases of parotid carcinomas, FNA correctly diagnosed 21(6 histologically, and 15 were malignant), and failed in 11. Because the accuracy of the FNA findings was poor, we performed on open biopsy in 8 patients prior to the operation, and an accurate diagnosis of the histology and grading were obtained in all patients. The problem of contaminating the operative field with tumor cells in an open biopsy was solved by removing the skin during the operation and shortening the time between the open biopsy and the operation. Twelve of 14 patients accurately diagnosed histologically underwent the appropriate operation, while 6 of 9 patients diagnosed with benign tumors preoperatively underwent inappropriate operations. Forty persent of the patients underwent on inappropriate operation mainly because of inaccurate preoperative diagnosis. An open biopsy should be performed to accurately diagnose patients with parotid carcinomas and to improve their prognosis.