Palladium nanoparticles (PdNPs) were electrodeposited on the carbon ionic liquid electrode (CILE) for evaluating the assemblage for electrochemical determination of isoniazid (INH). The surface morphological investigation of the fabricated electrode by using scanning electron microscopy indicated efficient electrodeposition of PdNPs with the particle diameter of 30-100 nm when a constant potential of -0.2 V for duration of 60 s was applied. Electrocatalytic oxidation of isoniazid at this electrode was investigated in phosphate buffer solution (pH 7.0) using cyclic voltammetry. A highly reproducible and well-defined peak with a high electrocatalytic peak current was obtained for INH at a low overpotential of +0.34 V versus Ag/AgCl. Under optimized experimental conditions, linear relationship between anodic peak current and INH concentration in the ranges of 5.0 x 10(-6)-1.0 x 10(-4) and 1.5 x 10(-4)-2.6 x 10(-3) mol L-1 INH with a detection limit of 4.7 x 10(-7) mol L-1 was obtained. The procedure was successfully applied for analysis of INH in human blood serum and pharmaceutical samples. (C) 2015 Elsevier B.V. All rights reserved.