Novel hybridisation assay probes and mixtures of such probes for detecting a target sequence of one or mycobacteria optionally present in a sample. The probes may suitable be directed to target sequences of mycobacterial rDNA, precursor rRNA, or rRNA, said probes being capable of forming detectable hybrids. The probes are in particular directed to mycobacterial rDNA, to precursor rRNA, or to 23S, 16S or 5S rRNA The probes are useful for detecting the organisms in test samples such as sputum, laryngeal swabs, gastric lavage, bronchial washings, biopsies, aspirates, expectorates, body fluids (spinal, pleural, pericardial, synovial, blood, pus, bone marrow), urine, tissue sections as well as food samples, soil, air and water samples, and cultures thereof.