Forty microorganisms belonging to different taxonomical groups were used to catalyze the enantioselective reduction of ethyl 2-oxophenylbutyrate to afford the corresponding ethyl 2-hydroxy-4-phenylbutyrate. Several microorganisms led to over 99% ee of ethyl (S)-2-hydroxy-4-phenylbutyrate. Especially, we firstly found that the Candida boidinii CIOC21 could be effectively used for the enantioselective preparation the ethyl (R)-2-hydroxy-4-phenylbutyrate in pure aqueous medium with 99% ee, a key intermediate in the production of angiotensinconverting enzyme (ACE) inhibitors.