An efficient and scalable NAD(P) + regeneration system to promote alcohol dehydrogenase-catalysed oxidation reactions is reported. Indirect electrochemical oxidation of NADH was established with 2,2′-azino-bis-(3 ethyl-benzo-thiazoline-6-sulfonic acid) (ABTS), being the most efficient mediator amongst the candidates screened. ABTS exhibited very high catalytic performance of 1200 catalytic turnovers per hour. In a three-dimensional electrochemical cell with a high working electrode surface area of 24m 2 and optimised concentrations of substrate, enzyme, cofactor and mediator, TTNs of 1860 for the mediator and of 93 for the cofactor were measured. Besides, a maximum STY of 1.4gl −1 h −1 was determined. Here we show the highest TTN ever reported for a mediated NAD + regeneration in an electro-enzymatic process. The use of the three-dimensional electrochemical reactor led to an 8-fold improvement of the STY compared to a published system, based on a two-dimensional cell.