Iron oxides based nanomaterials attract the attention of researchers due to their small cost and applicability in various areas such as: magnetic storage devices, magnetic resonance imaging, drug delivery and cancer therapy, catalysis, magnetic ink and gas detectors [1]. Depending on the field of application, one must consider the size, shape, crystallinity, dispersibillity and magnetic properties of the nanoparticles. The size and morphology of the prepared particles can be controlled by carefully choosing the preparation method, the type of reagents used and their concentration in solution, the reaction temperature and the reaction time. Various salts are used as iron source for iron oxide nanoparticles. The metallic clusters as precursors for oxide nanoparticles are less studied. We used complex compounds synthesized in our laboratory as the source of iron or iron-other metal with pre-established ratio, and applied different methods for preparation of oxide nanoparticles in presence of a stabilizing agent. Thus, three strategies were approached to tune the characteristics of the iron oxide nanoparticles: •solvothermal method varying certain parameters (solvent nature, concentration of the stabilization agent, the type of metallic cluster) to obtain iron oxide nanoparticles with controlled size and shape; • thermal decomposition method in presence of excess of oleic acid as stabilizing agent, when amorphous nanoparticles were obtained. In specific conditions, the materials resulted as self-assembled organized structures; • by using biocompatible siloxane surfactants, the nanoparticles were functionalized making possible their dispersion in water.