The most common neoplasm of the larynx in children is papillomas. Although classified histologically as a benign neoplasm, this tumor has proved resistant to current methods of surgical therapy. A complete reappraisal of this disease suggested that a new comprehensive approach to this interesting tumor was needed. We propose a simultaneous three part investigation of the etiology and behavioral characteristics of laryngeal papillomas, using cell culture, virological techniques and clinical assessment in patients. Epithelial cell culture from laryngeal papilloma will be used for in vitro assessment of various types of immunotherapy and to provide material for viral studies. Human skin papillomas have been shown to be produced by papilloma viruses. Similarities in clinical behavior and histological pattern between skin warts and laryngeal papillomas suggest that the latter may also be caused by a papilloma virus. Virologic methods will be used to determine if a papilloma virus is present in laryngeal papilloma cells. Further, if such a virus is present and if sufficient viral antigen can be obtained, the level of antiviral antibody in patients sera could then be estimated. Promising clinical response in some of our patients with active disease has been obtained in a pilot study using transfer factor obtained from other patients who have experienced spontaneous remission. It is felt that the correlation of basic laboratory studies with the clinical features and progress of the disease is essential for the further understanding of the fundamental etiology of this disease and its subsequent immunological control.