A novel uric acid biosensor based on Fe3O4 nanoparticles (Fe3O4NPs) modified carbon paste electrode is described. Electron transfer characteristics of bare (CPE) and Fe3O4NP-modified carbon paste electrodes (Fe3O4/CPE) were studied by cyclic voltammetry and electrochemical impedance spectroscopy. The voltammetric study indicated that the incorporation of Fe3O4NPs into carbon paste increased the electroactive surface area of the electrode and improved electron transfer. Under the optimum working conditions, the purposed biosensor showed a linear response to uric acid from 0.16 mM to 2.11 mM with a detection limit of 0.08 mM. The biosensor exhibited high selectivity, good repeatability, reproducibility, and stability. Moreover, the construction and renewal procedure of the purposed biosensor is simple and inexpensive. Graphic abstract: [Figure not available: see fulltext.]