The tubberculin hypersensitivity to PPD-Rt 23 and PPD-B was tested on 543 children, 12 to 14 years old in "Estado da Guanabara", Braiil. The sensitivity to tuberculin proteins was found high. About 33,65% of the children showed strong reactions to PPD-Rt 23 in about 6,26% of the children population, what suggests a hypersensitivity due to the Battey bacillus or another mycobacteria more antigenically related with this microorganism than the M. tuberculosis.