A method for producing nanostructured multi-component or doped oxide particles and the particles produced therein. The process includes the steps of (i) dissolving salts of cations, which are either dopants or components of the final oxide, in an organic solvent; (ii) adding a dispersion of nanoparticles of a single component oxide to the liquid solution; (iii) heating the liquid solution to facilitate diffusion of cations into the nanoparticles; (iv) separating the solids from the liquid solution; and (v) heat treating the solids either to form the desired crystal structure in case of multi-component oxide or to render the homogeneous distribution of dopant cation in the host oxide structure. The process produces nanocrystalline multi-component or doped oxide nanoparticles with a particle size of 5 500 nm, more preferably 20 100 nm; the collection of particles have an average secondary (or aggregate) particle size is in the range of 25 2000 nm, preferably of less than 500 nm.