Benzothiazoles are given priority among other persistent organic pollutants of the natural environment due to their importance for agriculture and variety of industrial processes. Until recently, only a few microorganisms have been shown to degrade some benzothiazoles as pure culture. In view of the importance to microbiological processes of detoxication, our purpose was to select some indigenous strains that will use benzothiazole (BT) and 2-hydroxybenzothiazole (OBT) as the only source of nitrogen, carbon and energy and to study the products of microbial transformation. For the search of benzothiazole-degrading microorganisms, the soil heterocyclic compounds-degrading microorganisms were used (collection of the laboratory of Biotransformation of Xenobiotics, Institute of Microbiology, Chisinau). BT and OBT transformation was monitored in “resting cells” experiments by chromatography (TLC, HPLC), NMR and mass-spectrometry methods. Benzothiazole derivatives are very recalcitrant and difficult to degrade. The screening of 29 fungi and 37 bacterial strains in a liquid mineral medium made it possible to select strains belonging to Penicillium and Aspergillus genus -having various capacities to metabolize BT and OBT. Positive results were obtained when: 1) nitrogen salt was removed from the mineral medium; 2) xenobiotic concentration was reduced to 50 mg/l for BT and 100 mg/l for OBT. It was found that the selected micromycetes differ from each other both regarding the rate of OBT and BT degradation and the metabolite spectrum. The most active strains were the soil fungi Penicillium sp.24 and Penicillium sp.77, which biotransformed, within two days of incubation, 35-56% of organic compound. The degradation of BT and OBT by these active strains takes place by an oxidative pathway, via successive hydroxylation reactions: first on the thiazole ring and then in position 6 of the aromatic ring. The hydroxylated BT products - OBT and 2,6-dihydroxybenzothiazole (diOBT) – were detected as intermediates in BT degradation, and diOBT was found to be an intermediate in OBT degradation by penicillii, as previously shown with bacteria. Other metabolites corresponding to the cleavage of the thiazole ring have been detected. Further investigations on the structure of the products of ring opening are in progress.