Between 1972--1974 26 children (15 boys and 11 girls) aged 11--14, with sarcoidosis were observed in county Szabolcs-Szatmár, Hungary. The number of cases varied between 1--6 per year, so the incidence of sarcoidosis is about 2--11/100000 for the age group 10--14 years of this county. Sarcoidosis was detected because of complaints in 4 cases, and by mass radiographic surveys in 22 cases. In each of the patients the thoracic form of sarcoidosis was in the foreground (in 6 cases mild bilateral hilar adenopathy, in 2 cases only unilateral hilar adenopathy, in 18 cases typical BHL-syndrome sometimes with "tumorous" adenopathy and in 7 cases out of the 18, hilar adenopathy and mottling in the lungs). The laboratory data were an unsatisfactory basis for the diagnosis. The tuberculin test was negative in 65 per cent. There was no proof for infection with atypical mycobacteria by intradermal tests. The most important basis of diagnosis was the biopsy (mediastinoscopy), especially in cases of simultaneous infection with tuberculosis. Prednisone treatment was carried out in the first place in cases of adenopathy and mottling, and in the cases of elevated serum calcium. Prednisone resistance was observed in two cases; in one of the patients it was secondary since it manifested itself only at the relapse of the BHL-syndrome; in the other patient the drug resistance was primary.