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This article reports the highly selective and sensitive uric acid quantification in the presence of ascorbic acid using glassy carbon electrodes (GCEs) modified with multi-wall carbon nanotubes (MWCNTs) dispersed in polylysine (Plys) (GCE/MWCNT-Plys). The electrocatalytic activity of MWCNT deposited on GCEs has allowed an important decrease in the overvoltages for ascorbic acid oxidation (440mV), making possible the clear definition of the oxidation processes of ascorbic acid and uric acid. Two protocols for uric acid quantification are described, the direct differential pulse voltammetry (DPV) detection, and the DPV-adsorptive stripping detection with medium exchange. For the direct determination of uric acid, the sensitivities were (9.8±0.2)×10⁴μAM⁻¹ (r=0.994), and (10.7±0.2)×10⁴μAM⁻¹ (r=0.994) in the presence and absence of 1.0mM ascorbic acid, respectively. The detection limit for uric acid in the …