We have employed the polymerase chain reaction (PCR) to detect Human Papillomavirus (HPV) type 16 in oral squames and mononuclear cells from 62 healthy young adult volunteers. Two groups were screened for the presence of this virus, but in not all cases was DNA obtained from the scrapes. In the first (n = 30), the results show that 43% of normal individuals harbour HPV 16 (a genital type) in their buccal mucosa, epithelium of dorsum of tongue and hard palate. In the second group (n = 18), 44% of individuals were positive for HPV 16 in their oral epithelial scrapes, while only 6% were positive for the same virus in mononuclear cells. Interestingly, in 2 cases, peripheral blood lymphocyte DNA gave a positive reaction with the HPV 16 primers. To investigate possible HPV infection of lymphocytes, a further 42 lymphocyte samples, taken from the same age group as the epithelial study group, were analysed. None of these lymphocytes were positive for the presence of HPV 16 DNA.