The aetiology of oral cancer is thought to be multifactorial. Apart from the two known major risk factors (tobacco and alcohol), a viral aetiology has been proposed, with special reference to human papillomavirus (HPV). 35 cases of oral squamous cell carcinoma (OSCC), seen at the Departments of Oral and Maxillofacial Surgery and Oral Pathology and Otolaryngology of the Free University of Amsterdam, were analysed as well as 12 biopsies of clinically and histologically normal gingival mucosa collected from healthy individuals after tooth extractions, using the polymerase chain reaction (PCR) and two different sets of primers that are able to detect a broad spectrum of HPV types. An overall HPV positivity of 54.3% in OSCC was found, the majority of positive cases (78.9%) harbouring HPV type 16. In contrast, no positivity for HPV was detected in the clinically normal oral mucosal samples analysed. Furthermore, a significant association between HPV presence and age was found: patients older than 60 years showed a lower prevalence of the virus (29.4%) compared with patients below this age (77.8%) (P < 0.05). The results from the present study suggest an association between HPV and OSCC, particularly in patients under the seventh decade.