Nanomedicine holds enormous promise for the improved prevention, detection and treatment of disease. Yet, at the same time, countervailing concerns about the potential safety risks of nano-technologies generally, and nanomedical products specifically, threaten to derail or at least delay the introduction and commercial viability of many nanomedicine applications. All around the globe, national governments are struggling with balancing these competing benefits and risks of nanotechnology in the medical and other sectors. It is becoming increasingly clear that reasonable, effective and predictable regulatory structures will be critical to the successful implementation of nanotechnology. The question examined in this paper is whether there are mechanisms of international harmonization or cooperation that can facilitate the development of more effective and efficient regulatory regimes for nanomedicine?Part I of this paper briefly summarizes the promise of nanomedicine as well as potential concerns about the risks of nanomedical applications that will require regulatory oversight. In Part II, we analyze the various factors weighing for and against attempts to harmonize regulatory requirements at the international level. Finally, in Part III we identify some specific existing or feasible mechanisms that may be useful for fostering international harmonization in the regulation of nanomedicine.