Together 35 papillomas of the larynx (8 juveniles, 27 adults) were studied for the presence of HPV-DNA by means of nucleic acid hybridization. The hybridization procedure was carried out "in situ" with biotinylated probes of HPV 6/11 and 16/18 under stringent conditions. The results are shown in Table 1. In all juvenile papillomas we detected HPV 6/11, but we did not find positive signals after hybridization with HPV 16/18, 25 (92.6%) of the examinated adult papillomas were HPV 6/11 positive. The detection procedure of HPV 16/18 was positive twice (11.8%). The results of our studies support the hypothesis of HPV 6/11 in development of larynxpapillomas.