A newly devised 7H12 cultivation method combined with nested PCR assay using Mycobacterium tuberculosis-specific primers was evaluated for its usefulness to detect and identify tubercle bacilli in 38 sputum samples. This method yielded detection and identification of M. tuberculosis in sputum specimens with excellent sensitivity, specificity, and rapidity, when compared to the cultivation method using Ogawa egg medium or the 7H12 cultivation method in which bacterial growth is monitored by microscopy (7H12-microscopy method) with the same sensitivity as that of the BACTEC 460 TB system.