In this paper, the possibility of using an electrochemically activated carbon-paste electrode (ECA-CPE) for the determination of morin has been studied. It is established that the oxidation current increases 1.85 times in comparison with untreated CPE. The adsorption nature of the anodic current and the number of electrons taking part in the oxidation of morin on ECA-CPE was established. The optimal conditions for the determination of morin (pH $=$ 4, E$_{ads\, }=$ 200~mV, t$_{ads\, }=$ 180 s) were established. Using square-wave voltammetry (A $=$ 35 mV, $\nu =$ 25 Hz, $\upsilon =$ 100 mV/s) it is possible to determine morin in the range of concentrations of 6-0.8 μM (with 0.314 μA\μM sensitivity) and 0.8-0.16 μM (with 0.557 μA/μM sensitivity). The developed sensor was tested for the determination of morin in model solutions and Coffea arabica extracts with RSD lower than 4.5%.