In this article, magnetic fluids based on metal ferrites, namely NiFe2O4, CoFe2O4, and FeFe2O4, were synthesized. The sizes of the obtained magnetic nanoparticles were studied using transmission electron microscopy, revealing an approximate size of 40 nm. This result was confirmed by X-ray diffraction analysis. The magnetization of these synthesized magnetic nanoparticles was measured using a vibrating magnetometer.