Human papilloma virus (HPV) may have an important role in oral carcinoma etiology. Our work compares the presence of HPV in the epithelium of oral mucosa of patients with oral carcinoma with other factors of risk (smoking, alcohol, chronic mucosal trauma). We studied 33 patients operated for oral cancer at St. Salvatore Hospital in l'Aquila, in January-December 1990. The presence of HPV was proved by a direct valuation of morphological signs (coilocytosis, nuclear inclusions, etc.) and by immunohistochemical technique with primary antibodies against structural virus antigens. Among the 33 patients 19 (57.6%) were positive for HPV and 14 (42.4%) were negative. Among the HPV positive subjects 13 were smokers, 11 usually assumed alcohol and 6 had chronic mucosal trauma. Among the HPV negative subjects 9 were smokers, 7 assumed alcohol and 3 had chronic mucosal trauma. The statistical evaluation of data showed the lack of significance of viral infection compared to other factors of risk. In spite of a few cases examined, we suppose that HPV doesn't play a primary role in oral cancerogenesis, but is a concomitant cause with other factors of risk.