In order to investigate the possibility of the microbial degradation of the persistent pollutant 3, 3`, 4, 4`-tetrachloroazobenzene (TCAB) in our environment, four strains of microorganisms were isolated from industrial wastes by the enrichment technique. They were identified as Achromobacter group VD, Pseudomonas alcaligenes, Moraxella spp., and Alcaligenes faecalis, respectively. These microorganisms utilized TCAB as a sole carbon source in the MM₂ salt medium.