Although tobacco, alcohol abuse and betel nut chewing habit are well recognized risk factors for oral squamouscell carcinoma (OSCC), there is evidence to indicate that human papillomavirus (HPV) may also play someinducing role. The purpose of this study was to investigate the presence of HPV in Thai patients with oralsquamous cell carcinoma, leukoplakia and lichen planus using the polymerase chain reaction (PCR). Biopsies oforal squamous cell carcinoma, leukoplakia and lichen planus were obtained from 65 patients, 15 males and 50females, aged between 30-88 years old. Extracted DNA was evaluated for HPV infections by PCR analysis usingconsensus primers specific for L1 region of HPV. Only one sample (1.54%) was positive, suggesting that HPVmay not play an important role in this group of Thai patients.