Nanomedicine is currently showing great promise for new methods of diagnosing and treating many diseases, particularly in kidney disease and transplantation. The unique properties of nanoparticles arise from the diversity of size effects, used to design targeted nanoparticles for specific cells or tissues, taking renal clearance and tubular secretion mechanisms into account. The design of surface particles on nanoparticles offers a wide range of possibilities, among which antibodies play an important role. Nanoparticles find applications in encapsulated drug delivery systems containing immunosuppressants and other drugs, in imaging, gene therapies and many other branches of medicine. They have the potential to revolutionize kidney transplantation by reducing and preventing ischemia–reperfusion injury, more efficiently delivering drugs to the graft site while avoiding systemic effects, accurately localizing and visualising the diseased site and enabling continuous monitoring of graft function. So far, there are known nanoparticles with no toxic effects on human tissue, although further studies are still needed to confirm their safety.