Presenting a study about Human Papillomavirus (HPV) determination by immunohistochemistry and "in situ" hybridization, in 25 samples of squamous cell papillomata (15 tonsilar and 10 laryngeal lesions). Five cases resulted positive for HPV: 2 of them for immunohistochemical probes, other 2 for "in situ" hybridization and only 1 cas showed its positivity for both techniques. All these samples belonging to laryngeal cases. No significant differences were found in antecedents, clinical and histological features related with results obtained. Two patients developed a laryngeal carcinoma after papilloma and they had positive "in situ" hybridization. Literature about diagnosis of HPV-infection was revised.