In the present paper the results of a study of new planar composite nanosystems on the basis of complexes formed by amphiphilic polyamine, magnetite nanoparticles, and DNA molecules are presented. Amphiphilic polyamine stearylspermine is synthesized and characterized by the FTIR spectroscopy technique. It is found that a Langmuir monolayer on an aqueous subphase surface can be formed by synthesized stearylspermine molecules. The stearylspermine Langmuir monolayer compression isotherm changes caused by the interaction of a monolayer with colloid magnetite nanoparticles and DNA molecules from the aqueous phase have been studied. The monolayer nanostructures on the surface of mica substrate-Langmuir-Blodgett films of complexes formed by stearylspermine, magnetite nanoparticles, and DNA molecules are formed. The structure of the obtained monolayer films was investigated using the AFM scanning probe technique. Possibilities for the formation of polycomplexes which comprise stearylspermine molecules, functional inorganic nanoparticles, and polymers have been discussed.