The present study describes the first electroanalytical investigation and the development of a novel voltammetric method for a sensitive, simple, fast, cheap and eco-friendly determination of eltrombopag (ELT). At a borondoped diamond electrode pretreated electrochemically (anodic and subsequent cathodic), the compound presented one or two oxidation steps at relatively low positive potentials within the pH range 6.0-12.0 by employing square-wave voltammetry. The sensitivity of the measurements was significantly enhanced with the positive effect of cetyltrimethylammonium bromide (CTAB) under the accumulation condition. In Britton-Robinson buffer pH 12.0 containing 2 x 10(-4) mol L-1 CTAB (after 30 s accumulation at open-circuit condition), there was a linear dependence of peak current at +0.19 V (vs. Ag/AgCl) and ELT concentration in the range of 0.1-12.5 mu g mL(-1) (2.3 x 10(-7)-2.8 x 10(-5) mol L-1) with a detection limit of 0.0125 mu g mL(-1) (5.7 x 10(-8) mol L-1). The developed approach could be used for ELT determination in commercial tablet formulations.