The interactions of furazolidone (Fu) with double‐stranded calf thymus DNA (dsDNA) on the multiwalled carbon nanotubes modified glassy carbon electrode (MWCNT/GCE) have been studied by voltammetry and UV‐vis spectroscopy. The binding constants of Fu with DNA and the stoichiometric coefficient according to the Hill’s model have been determined. A detailed analysis of cyclic voltammograms gave fundamental electrochemical parameters including the electroactive surface coverage (Γ), the transfer coefficient (α), and the heterogeneous rate constant (ks). Two linear calibration curves were obtained for DNA detection in the concentration ranges of 40–100 µ L−1 and 100–1000 µg L−1 with a detection limit of 25 µg L−1.