The aim of this work was the development and characterization of iron oxide nanoparticles with magnetite phases (IONPs)-hydroxyapatite (HAp) composites. In this article, the chemical coprecipitation method was used to synthesize three different nanomaterials: IONPs, HAp, and IONPs-HAp composite. Rietveld analysis of the X-ray diffraction (XRD) revealed the crystal lattice parameters and presence of HAp and IONPS after synthesis, which was carried out at a temperature of 120 °C inductively coupled plasma (ICP) was used to identify the trace elements present, Fourier transform infrared (FTIR) spectroscopy to verify the functional groups present in each material and efficiency of washes for the composite material, transmission electron microscopy (TEM) to observe the morphology and nanoparticle size for IONPs 11 nm and IONPs-HAp 15 nm. ζ potential measurements to investigate the surface charges for all samples had a positive value, the apatite samples showed a very stable behavior, and vibrating sample magnetometry (VSM) to evaluate the magnetic properties showed that IONPs and IONPs-HAp composite exhibit superparamagnetic behavior, while HAp nanoparticles show diamagnetic behavior. It was also shown that the saturation magnetization and magnetic moments of the IONPs do not change upon formation of the IONPs-HAp composite.