Structure analysis of multifunctional nanoparticles could be a complex process. In this paper, we demonstratethe step-by-step techniques used for identifying the structure of the CoFe−Fe3O4 nanoparticles, which arecomposed of ∼4-nm CoFe cores and covered with ∼3-nm Fe3O4 polynanocrystallites. The techniquesdemonstrated are general and can be adopted for analysis of any nanoparticles of interest in physical chemistry.