More than 65 distinct types of human papillomavirus (HPV) have been identified to date. Several of the HPV types have been proposed as etiologic agents of squamous cell carcinoma. In the oral cavity, HPVs have been found associated with several benign squamous cell proliferations. Evidence from histology and DNA hybridization studies suggests that HPV is also involved in oral carcinogenesis. It is apparent, however, that substantial amount of confusion exists in the diagnosis of oral HPV infections. The keratotic, papillary lesions in the oral cavity are usually small and easily overlooked. The gross appearance of these viral lesions is not distinct enough to be readily diagnosed by the clinicians. Degenerative changes found on oral mucosa frequently simulate koilocytosis. Thus, caution should be exercised to avoid overdiagnosis of HPV infection in the oral cavity. The present review summarizes the current evidence available on HPV infections in general and on oral HPV infections in particular. The diagnostic techniques available as well as the problems encountered in the distinction of these lesions are also discussed in short.