Human papillomavirus (HPV) type 6e DNA was detected in a laryngeal papilloma, in a papilloma recurring after an interval of six years and in the counterpart clinically-normal false cord of the same patient. No detectable subgroup change of HPV DNA occurred during the clinical course, which included therapy by CO2 laser followed by intramuscular alpha-interferon injection. The data demonstrated a single subtype of HPV to have persisted, and the prevention of a recurrence of laryngeal papilloma during our patient's long clinical course to have failed, in spite of the interferon treatment.