14 children and adults suffering from laryngeal papillomatosis were treated with an inactivated tissue culture virus vaccine. The vaccine was produced from a virus of the papova group isolated out of juvenile laryngeal papillomatosis. In all vaccinated patients, objective regression of tumor mass was observed, mostly without any operative procedure. In 5 patients even with an operation microscope no residula papillomatous tissue could be seen after treatment. In 7 patients with laryngeal papillomas which had been treated for years by repeated surgery, immunotherapy induced regression of 6-12 months duration. Thereafter, recurrences were found which were clinically silent but visible by microscopy. A second vaccination was succesful in 8 of 10 patients. The vaccine treatment showed no side effects.