Research on the synthesis and characterization of manganese ferrite nanoparticles with the coprecipitation method at low temperature has been carried out. The purpose of this study was to the determine the effect of low temperature on the microstructure of MnFe2O4 nanoparticles. The synthesis of nanoparticles carried out using the coprecipitation method, characterization using XRD and SEM. XRD measurement data were processed using Software Origin 9.0, obtained a crystalline phase diffraction pattern of MnFe2O4 and a crystal with a spinel structure. The crystallite size obtained was 5,79 nm at 90 °C, 5,65 nm at 120 °C and 5,47 nm at 150 °C with an average lattice parameter of 9,16 Å. Crystallite size can be controlled using the synthesis method at low temperatures. The surface morphology of the SEM test showed that an average grain size of 5,93 nm was spherical with quite various sizes and clots.