Abstract: Carbon-encapsulated iron and nickel magnetic nanoparticles (CEMNPs) were synthesized from their salt precursors using an instant pyrolysis method. The morphologies, structural features and magnetic properties of the particles were investigated by transmission electron microscopy, X-ray diffraction, simultaneous thermogravimetry-differential scanning calorimetry and vibrating sample magnetometry. It was found that almost all of the CEMNPs were spherical, and their size changed from 10 to 30nm, whereas the size of the carbonencapsulated iron nanoparticles changed from 50 to 60nm. The magnetic properties of the products indicated that the carbon-encapsulated iron nanoparticles were paramagnetic and their properties were tunable with the iron content. The present approach is promising for large-scale production of CEMNPs.