A whole-cell mediated asymmetric reduction of oxcarbazepine 1 to S-licarbazepine 2, a key intermediate in the synthesis of Eslicarbazepine acetate, was achieved using the yeast strain Pichia methanolica 103660. The reduction was carried out in a biphasic system consisting of (1 : 1) de-ionized water and hexane. This organism catalyzed the reaction to yield the S-enantiomer 2 with excellent conversion (>98%) and enantiomeric excess (ee > 98%) within 24 h of incubation.