Recent epidemiological research has raised the possibility of a connection between viral infection by the human papilloma virus (HPV) and the existence of squamous cell carcinoma of the oral cavity and oroharynx (SCCa). Some 60 subtypes have been identified to date, and specific subtypes are associated with lesions or infections at specific tissue sites. Twenty-three patients with SCCa of the oral cavity were studied for the presence of HPV in their tumours. HPV DNA (all type 16) was isolated from four specimens (17.3 per cent) using the Polymerase Chain Reaction (PCR) method. The four patients were all over age 50, and had advanced tumours (two T3 and two T4) that originated in the oropharynx. Our data supports other reports in the literature, demonstrating the presence of HPV DNA type 16 within cells from oropharyngeal SCCa. We conclude that the PCR method is a useful and reliable method for the detection of HPV DNA within tumour cells.