A comparative study of two modifications of enzymic reduction of ethyl N-[2-[4-[(2-oxo-cyclohexyl)methyl]phenoxy]ethyl]carbamate (1), an insect juvenile hormone bioanalog, was performed using Saccharomyces cerevisiae in two bioreactors of different size, 250-ml shake-flask and 1-l fermenter. The two major products of this reduction were obtained in 45-49% (w/w) yields but with > 99% enantiomeric purity. Their absolute configurations were assigned as ethyl (1S,2S)-N-[2-[4-[(2-hydroxycyclohexyl)methyl]phenoxy]ethyl]carbamate (2a) and ethyl (1R,2S)-N-[2-[4-[(2-hydroxycyclohexyl)methyl]phenoxy]ethyl]carbamate (3a).