The present invention provides a method of specifically detecting the presence of one or more Mycobacteria of the M. tuberculosis complex, said method comprising detecting ilvC nucleic acid of one or more Mycobacteria of the M. tuberculosis complex in a sample under conditions that do not detect ilvC nucleic acid of the M. avium complex. The invention also provides methods of diagnosis and treatment of tuberculosis in a subject employing the specific detection ilvC nucleic acid of one or more Mycobacteria of the M. tuberculosis complex.