In this work, Fe 3 O 4 @ZnFe 2 O 4 core/shell nanoparticles were obtained by depositing ZnO by the wet chemistry method on the surface of Fe 3 O 4 nanoparticles seeds obtained by the chemical bath deposition method. Fe 3 O 4 and Fe 3 O 4 @ZnFe 2 O 4 were characterized by Field Emission Scanning Electron Microscopy, Energy Dispersive X-ray Spectrometry, Transmission Electron Microscopy, X-ray Diffraction, Ultraviolet–Visible Spectroscopy, Diffuse Reflectance, and Fourier Transformed Infrared Spectroscopy (FTIR). The Fe 3 O 4 @ZnFe 2 O 4 nanoparticles formed an urchin-like spheres morphology (corresponding to Fe 3 O 4 ) with a homogeneous shell of ZnFe 2 O 4 . XRD analysis showed a magnetite crystal structure for Fe 3 O 4 and a franklinite (ZnFe 2 O 4 ) crystal structure for the shell. Fe 3 O 4 @ZnFe 2 O 4 showed higher crystallinity when applying a heat treatment, showing a crystal size of 9.12 nm with heat treatment and 9.43 nm without heat treatment. The diffuse reflectance results suggested an indirect band gap of 1.85 eV for Fe 3 O 4 and two indirect band gaps of 1.85 eV and 2.54 eV for Fe 3 O 4 @ZnFe 2 O 4 . The FTIR results showed the effect of heat treatment on Fe 3 O 4 @ZnFe 2 O 4 core/shell nanoparticles. A simple method was used for the synthesis of Fe 3 O 4 @ZnFe 2 O 4 .