Resting cells of the transpositional mutant strain B-9, which was obtained from the aniline-assimilating Pseudomonas sp. AW-2 and produced catechol from aniline, exhibited the ability to oxidize 16 aromatic amines among 26 tested. Thirteen products from the 16 amines mere purified and crystallized, Analytical data including mass and nuclear magnetic resonance spectra of the products showed that methyl, dimethy, ethyl, chloro-, fluoro-, and hydroxyl derivatives of aniline were converted to the corresponding catechols, In particular, catechols were synthesized from o-, m-, and p-toluidine, p-fluoroaniline, and m-aminophenol at a conversion rate of 100%. It was revealed that strain B-9 cells exhibited extensive substrate specificity for aromatic amines, regardless of the position of substituent groups in their isomers.