The magnetic MFe2O4 (M=Co, Ni) nanoparticles are synthesized using a hydrothermal synthesis method in ethylene glycol (EG) solution. Their morphologies, structures, surface properties and magnetism are characterized by field emission scanning electron microscopy (FE-SEM), powder X-ray diffraction (XRD), fourier transform infrared (FTIR) absorption spectra, and vibrating sample magnetometer (VSM), respectively. The nickel ferrite and the cobalt ferrite samples are nearly spherical and homogeneous nanoparticles with average size range of about 90 nm (NiFe2O4) and 30 nm (CoFe2O4). XRD patterns confirm that the NiFe2O4 samples belong to the cubic structure and the CoFe2O4 samples are the rhombohedral structure. The NiFe2O4 nanoparticles are superparamagnetic at room temperature, while the CoFe2O4 nanoparticles are sub-ferromagnetic at room temperature and possess higher saturation magnetization.