The electrochemical behavior of methimazole (MTZ) at fluorine-doped tin oxide electrodes has been studied by cyclic (CV) and square wave (SWV) voltammetric techniques. The CV studies were performed in a wide range of potential scan rates and pHs. The results showed an irreversible, diffusion controlled process for the electrochemical reaction of MTZ. Under the optimum conditions SVW measurements showed that a linear relationship between MTZ anodic peak current vs. concentration exists in the range 6 x 10(-6)-240 x 10(-6) mol L-1 using buffer at pH 3.0. A 1.98 x 10(-6) mol L-1 detection limit, relative standard deviation (RSD) below 2.0% and good sensitivity was obtained. Therefore these electrodes are promising candidates for the reliable electrochemical determination of MTZ in pharmaceutical preparations with good selectivity and suitable recovery. (C) 2012 Elsevier Ltd. All rights reserved.