Mantoux results were examined for 29 children with culture-proven nontuberculous mycobacterial lymphadenitis, and 4 species were isolated: Mycobacterium avium-intracellulare complex (from 14 patients [48%]), Mycobacterium haemophilum (from 12 [41%]), Mycobacterium simiae (from 2 [7%]), and Mycobacterium scrofulaceum (from 1 [3%]); the median indurations for each species were 15.5 mm, 14.5 mm, 20 mm, and 23 mm, respectively, and in 17 cases (59%), they were > or =15 mm. In regions with a low incidence of tuberculosis, lymphadenitis thought to be due to nontuberculous mycobacteria should be managed as such, regardless of Mantoux results, thereby avoiding antituberculosis treatment.