The authors reviewed the clinical records and the histopathological preparations of 78 cases of Warthin's tumours (WTs), treated at the Department of Dental Sciences, Centre for the Study of Oral Tumours, of the University of Bari. All the surgical specimens had been fixed in neutral buffered formalin, sampled according to the step-serial, whole-specimen sectioning technique, embedded in paraffin and stained with haematoxylin-eosin, periodic acid Schiff and Gomori's reticulin. The results showed that Warthin's tumours characteristically affect the parotid gland, and most frequently arise in adults (mean age=57 years) and in males (95%). Multiple tumours were detected in 16 cases (20.5%), and five of these were bilateral (6.5%). One of the multifocal tumours involved an intra-parotideal lymph node and the laryngeal piriform sinus. In addition, 13 cases (16.6%) were associated with other malignancies. These data indicate that multiple (synchronous or metachronous) WTs may occur more frequently than previously reported. The high rate of multiple WTs detected in the current study may result from extensive and accurate sampling of these neoplasms for histopathological evaluation. Consequently, complete preoperative work-up of patients harbouring parotideal tumours consistent with or suspicious for WT is necessary. The work-up should include CT scans and/or magnetic resonance imaging of both parotid glands, to exclude the occurrence of multiple tumours, which may be clinically undetectable. Also, fine needle aspiration biopsy may be an accurate tool for excluding malignant neoplasms and for better planning subsequent surgical procedures. These usually consist in (bilateral) superficial parotidectomy and should be followed by long term follow up of the patients, in view of possible metachronous WTs, even after prolonged time intervals.