In recent years the tendency towards the activation of the epidemic process of diphtheria, i.e. the appearance of cases of diphtheria simultaneously with the increased levels of circulation of toxigenic and nontoxigenic Corynebacterium diphtheriae and with antitoxic immunity characteristics in children and adults constantly remaining low, has been registered. For the effective control of diphtheria, the profound study of such problems as bacterial carriership, antibacterial immunity and the development of supplementary means of specific prophylaxis is necessary.