<p>The electrochemical behavior of rutin on cerium oxide/cobalt phthalocyanine-multiwalled carbon nanotube-modified glassy carbon electrode (CeO₂/MWCNT-CoPc/GCE) film was examined using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and amperometry in a Britton-Robinson buffer at pH 3.0. The physical and chemical characterization of the modified electrode was carried out with scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and electrochemical impedance spectroscopy (EIS). The DPV results showed that the developed CeO₂/MWCNT-CoPc/GCE demonstrated a linear concentration range between 1.0 × 10⁻⁷&#xa0;mol L⁻¹ and 2.8 × 10⁻⁵&#xa0;mol L⁻¹ with a limit of detection of 0.12 μ mol L⁻¹ (<i>S</i>/<i>N</i> = 3). In addition, amperometric measurements had higher sensitivity and revealed two distinct ranges of linear concentration. While the first linear range extends from 3.5&#xa0;nmol L⁻¹ to 0.17&#xa0;μmol L⁻¹, the second linear range was 0.4&#xa0;μmol L⁻¹ to 40.1&#xa0;μmol L⁻¹. The equations were obtained as <i>i</i>ₚ (μA) = 73.659 × <i>C</i>_Rutin (μmol L⁻¹) + 2.0432 and <i>i</i>ₚ (μA) = 3.4788 × <i>C</i>_Rutin (μmol L⁻¹) + 17.928, respectively. From the first linear range curve, LOD was found as 1.3&#xa0;nmol L⁻¹ (<i>S</i>/<i>N</i> = 3). The CeO₂/MWCNT-CoPc/GCE presented satisfactory results for reproducibility, stability, and selectivity. This technique was able to quantify rutin in tablet forms with complete accuracy and precision.</p>