We isolated a fungal strain HS-1 utilizing either ethylene glycol dibenzoate or ethyl benzoate as sole source of carbon and energy, and identified it as Aspergillus nomius, based on morphological and rDNA analyses. An enzyme hydrolyzing the esters was purified from the culture supernatant of the strain to an electrophoretically homogeneous state. The enzyme was a carboxyl esterase with a monomeric structure, of which the molecular mass was about 60000, and inhibited by phenylmethylsulfonyl fluoride. The enzyme hydrolyzed various benzoate esters and p-nitrophenyl esters, and its hydrolysis rates for the most favorable substrates, n-butyl benzoate and p-nitrophenyl valerate, were comparable.