The difference in the magnetic properties between two lanthanum manganite nanopowders with identical phase and chemical composition is discussed in terms of the influence of nanopowder synthesis conditions on their properties.The aim of this investigation was to show the influence of precursor type and structure on the structure and properties of final La 0.7 Sr 0.3 MnO 3 nanopowders obtained by precipitation technique. The forming of a complex structure of precursor materials during drying and inheritance at firing stage led to the formation of bimodal particle size distribution and magnetic properties typical of coarse powders. The correct choice of precursor material and the technological conditions of the drying and firing stage were allowed for the creation of a uniform powder structure with special magnetic properties.We showed that the magnetic properties of nanopowders were not always determined by chemical or phase composition and mean particle size of synthesized powders. The difference in precipitation process can lead to unpredictable and catastrophic results, and masked the effect of nanoparticles on the magnetic properties of the material.