The performance of the MB-Check system (Roche) in the recovery of mycobacteria from clinical specimens was compared with that of the Bactec radiometric system and conventional culture on Lowenstein-Jensen medium A total of 1,582 clinical specimens were used for the study; 74 yielded mycobacteria. Organisms of the Mycobacterium tuberculosis and Mycobacterium avium complexes accounted for the majority of isolates. The rate of recovery of all mycobacteria with the Bactec system was 91.9 %, with the MB-Check system 79.7 % and on Lowenstein-Jensen medium only 54.1 %. Combination of the Bactec and MB-Check systems allowed recovery of 100 % of isolates. The Bactec system showed a faster detection time than the other two methods.