This work proposes a simple and very sensitive method for electrochemical determination of citalopram by differential pulse voltammetry (DPV) using glassy carbon electrode. The cyclic voltammetry measurements proved that citalopram undergoes irreversible, adsorption-controlled, two-electron oxidation process, accompanied by the release of two protons. The influence of different measurement conditions, such as type and pH of supporting electrolyte solution, as well as DPV parameters was investigated. The glassy carbon electrode (GCE) exhibits fast linear response toward citalopram oxidation in concentration ranges of 0.05-10 mu mol L-1 and 10-115 mu mol L-1 with detection limit (LOD) of 0.036 mu mol L-1. The proposed method provides low detection limit, high accuracy and precision with good selectivity in comparison to previously reported methods. The applicability of developed method was tested by determination of citalopram in pharmaceuticals and spiked tap, river and waste water samples. (C) 2019 The Electrochemical Society.