Electrodeposition of the conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT) in deep eutectic solvents (DES), prepared by the simple mixing and heating of an H-bond acceptor, choline chloride and H-bond donors such as urea, ethylene glycol and glycerol, is described. The PEDOT modified glassy carbon electrodes prepared in different DES and in the presence of conventional aqueous surfactants or HClO4 media were characterized during and after growth by electrochemical and quartz crystal microbalance studies. PEDOT synthesized in the best performing DES medium, choline chloride - urea (Reline) in the presence of HClO4, was used for the sensing of the biologically relevant molecules ascorbic acid, dopamine and uric acid. The sensing characteristics were compared with those of PEDOT-modified electrodes prepared in aqueous media. (C) 2015 Elsevier Ltd. All rights reserved.