Mn_xFe_3-xO₄ powders have been fabricated by using sol-gel methods; their crystallographic and magnetic properties were investigated by using X-ray diffraction, scanning electron microscopy, Mössbauer spectroscopy, and vibrating sample magnetometer. The Mn_xFe_3-xO₄ ferrite powders annealed at 500 ^oC had a single spinel structure regardless of the Mn²⁺-doping amount and their lattice constants became larger as the Mn²⁺ concentration was increased. Their Mössbauer spectra measured at room temperature were fitted with 2 Zeeman sextets due to the tetrahedral and octahedral sites of Fe ions, which made them ferrimagnetic. The magnetic behavior of Mn_xFe_3-xO₄ powders showed that the  Mn²⁺-doping amount made their saturation magnetization increase, but there were no severe effects on their coercivities. The saturation magnetization of the Mn_xFe_3-xO₄ powder varied from 38 emu/g to 70.0 emu/g and their minimum coercivity was 111.1 Oe.