Papilloma of the larynx continues to be an enigma in its etiology and therapy. The best evidence to date suggests that a virus presumably one of the papova virus group, is responsible and there are some immunologic trial in management of laryngeal papilloma with autogenous vaccination, transfer factor or leukokinase. In the known virus-caused skin wart, impairement of cell mediated immunity is reported in literatures and DNCB (dinitrochlorobenzene) sensitization is a proven effective immunotherapy. Assessment of cell mediated immunity in laryngeal papilloma and therapeutic evaluation of DNCB sensitization revealed 1) Cell mediated immunity in laryngeal papilloma was represented by 55.6% of positive reaction to DNCB and 51% of T cell count. 2) A significant improvement of T cell count was observed after DNCB sensitization. 3) 78.6% of patients responded to DNCB sensitization and 57.1% of patients revealed remission. 4) In the histological study, cases of improvement revealed quantitative change of the epithelial hyperplasia.