Recent progress in nanotechnology and electrochemical methods can be applied to fine control of the size, crystal structure, and surface properties of iron oxide nanoparticles. Here we appliedcathodic electrochemical deposition (CED) as an efficient and effective tactic for synthesisand double coating of surface of superparamagnetic iron oxide nanoparticles (SPIONs). In first step, bare Fe3O4 nanoparticles were prepared by CED method using a molar ratio of Fe3+:Fe2+ of 2:1. In the next step, the surface of nanoparticles was double coated with dextran (DEX) and polyethylene glycol (PEG) during the CED procedure, and PEG/DEX coated SPIONs were obtained. The prepared NPs were characterized using powderX-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic light scattering (DLS), vibrating sample magnetometer (VSM) and Field-emission scanning and transmission electron microscopy (FE-SEM and TEM). The XRD results confirmed that both deposited NPs have pure magnetite. FTIR results analysis indicated the existence of two coats (i.e. PEG and DEX) on the surface of depositedparticles. TG analysis exhibited the value of coat on the NPs surface is about 36%. The superparamagnetic properties of both prepared NPs were verified by VSM data, where the PEG/DEX coated NPs showed high magnetization value (Ms=30 emu/g), and negligible coercivity (Ce=0.95 Oe) and remanence (Mr=0.44 emu/g) values. The obtained results confirmed that the prepared Fe3O4 nanoparticles have suitable physico-chemical and magnetic properties for biomedical applications. In final, CED method can be proposed for facile preparation and in situ surface coating of superparamagnetic nanoparticles.