More than 10,000 first-to-sixth year students have undergone the Mantoux test (MT) for 36 years. Before 1980, the tuberculin sensitivity of the students declined rapidly (as high as 3% per year), then more slowly (1%), persons with tuberculin hypersensitivity reduced in number, and the previously observed rise in the proportion of tuberculin-positive persons among the first-to-second year students becoming fourth-to-sixth year ones. Recently, the number of MT-positive students has stopped increasing, but there has been a growth in the share of persons with an indurate of MT with 2 TE in 10-20 min (from 36.1e4.0 to 51.3e4.0%) with the still permanent proportion of tuberculin-hypersensitive students and without any increase in the incidence of tuberculosis among pupils. The authors hold that this phenomenon is the first sign of poor epidemiology. In this connection, they consider that mass MT with 2 TE performed in individuals with an indurate of above 10 mm is noteworthy as this is a growth index of the specific sensitization of the population and they are to be systematically tested.