The electrochemical oxidation of alizarin red-S has been studied using cyclic and differential pulse voltammetry, double step chronocoulometry and impedance spectroscopy in aqueous solution on glassy carbon electrode. The results revealed that alizarin red-S shows one oxidation peak and two reduction peaks. Electrochemical adsorption of alizarin red S was also studied in more details on glassy carbon surface. Double layer charge was calculated by chronocoulometric measurement in two ways, by using organic solvent for diminishing surface adsorption and by using a blank solution without alizarin red S. Obtained results showed that alizarin red-S adsorbed on glassy carbon in multi-layer arrays. Computational calculations were done by Chem Bio 3D software and Gaussian software on B3LYP/6-311(++) (d, p) level of theory. (C) 2016 The Electrochemical Society. All rights reserved.