Dipeptidyl peptidase IV is ecto-enzyme which is present on the cell surface of large number of cells and particularly of T-lymphocytes. It takes part in immune reactions and regulation of immune response, while antigen stimulation of cells increases percentage of expression of DPPIV on their cell surfaces. Since the immune response is different for chronic tonsillar disease of tonsilla palatine, idiopathic tonsillar hyperplasia ITH and recurrent tonsillitis RT, and considering the fact that DPPIV takes part in activation of T and B-lymphocytes stimulated by antigen, we presume that different activities of DPPIVexist in tonsillis and blood of persons diseased of different types of chronic tonsillitis, ITH and RT. The main goals of research are determination of activities of DPPIV on lymphocytes of tonsillas and serum of persons diseased of ITH and RT as well as histochemical and immunohistochemical determination of DPP IV localisation on lymphocytes of examed tonsillas. Two groups of patients are included: nineteen persons with ITH and thirteen persons with RT, while the control group was contained of thirty nine persons with diagnosis systematic lupus erythematosus (SLE) and fiftteen health persons. The research was done on 32 tonsillas created by tonsillectomia of persons with ITH and RT and 86 blood samples of all 86 persons. The results of research show histochemical localisation of enzyme activity of DPPIVin T-dependent zones of tonsilla and it is originating from activated T-lymphocytes. The enzyme activity of DPP IV on tonsillar lymphocytesis is higher in case of IHT compared with RT. By this research we conclude that deifferent activity of DPPIV on tonsillar lymphocytes for ITH and RTpresumes the difference of immuno response of tonsillas during these tonsillar diseases.