Amine-capped gamma-Fe2O3 nanoparticles were prepared by a simple one-step chemical solution method. By changing the type of iron salts, the phase composition and morphology of the samples were adjusted. The resultant products were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. The magnetic properties were also studied. Triethanolamine (TEA) plays an important role in the formation of magnetic structures. It can act as a precipitator, structure-directing agent, and surface-functionalizing agent. Successful attachment of amine groups to the surface of the magnetic nanoparticles was characterized.