The surface modification of various nanoparticles with silica has been exploited to increase their utilityfor bioapplications. However, silica encapsulation through conventional methods requires longreaction times (hours to days). Herein, we demonstrated that uniform and spherical silica encapsulationof magnetic nanoparticles can be achieved within 10 min via microwave irradiation after phasetransferring monodisperse magnetic nanoparticles from organic to water phase. In addition, we showedthat silica shell addition through microwave synthesis is more effective than conventional heatingmethods, such as a hot plate. The approach that we propose may be useful in preparing multifunctionalnano-probes, particularly for radiolabeling, which requires fast preparation times.