Labeling nanoparticles with radionuclides has been widely used to form multifunctional and multivalency agents for various biomedical applications. A variety of nanostructures including inorganic, organic and lipid nanoparticles have been labeled with positron or gamma emitting radioisotopes through versatile radiochemistry in a number of disease models to track their in vivo fate, image biomarkers, and monitor treatment response. This review briefly summarizes the recent applications of nanoparticles labeled with radionuclides for oncological, cardiovascular, and pulmonary theranostics.