A sensitive square wave voltammetry (SWV) method at screen-printed carbon electrodes was developed to determine imatinib in human urine using prepared multi-walled carbon nanotubes modified with carboxyl groups (MWCNT-COOH) as working electrode. The electrochemical behavior of the imatinib was investigated under several electrodes types and by three different voltammetric techniques: cyclic (CV), differential pulse (DPV) and square wave voltammetry (SWV). Quantitative analysis was carried out through its oxidation process at + 0.7 V, pH 7 and accumulation time of 120 s. The SWV method was linear in the range 50 nM-912 nM. The derivative signal of SW voltammogram resulted in limits of detection (LOD) and limit of quantification (LOQ) twice lower as SWV method (LOD 7 nM and LOQ 23 nM). The method was successfully applied for the determination of imatinib in real clinical urine samples from patients with chronic myeloid leukemia and the results were corroborated by capillary electrophoresis. Imatinib contained in patients urine samples was determined following the standard addition method using the same screen-printed electrode. In the present method, the only urine treatment was a simple dilution with the supporting buffer. (c) 2018 Elsevier Ltd. All rights reserved.