In this work, Fe3O4/TiO2 core–shell and composite nanopowders have been prepared to study their structural and magnetic properties. First a conventional sol–gel method was used to synthesize Fe3O4 and TiO2 nanoparticles separately. Then, they were combined to each other in two different geometries of core–shell and composite nanopowders. The samples were characterized by analytical techniques including XRD, TEM, SEM, and VSM. The results show the successful covering of the Fe3O4 nanoparticles surfaces with TiO2 in core–shell samples. In composite samples annealed at 400, 500, 600 °C, magnetite nanoparticles are distributed randomly in the TiO2 matrix. The magnetic measurements show that the core–shell sample, fabricated by a nonthermal method, has higher saturation magnetization than composite samples. Moreover, the values of the saturated magnetization of Fe3O4/TiO2 nanoparticles decreased with increasing calcined temperature.