Nanotechnology is the use of technology at the nano (10-9) level. Nanoscale devices differ from the conventional methods of diagnosing and treating diseases, and present certain advantages over them. Nanomedicine is a branch of the newly emerging field of nanotechnology. It is a rapidly developing discipline. By gaining access to many areas of the body which were thought to be unreachable, the nano devices possess the potential to not only detect diseases but also deliver treatment in ways unimagined before. The various nano devices used are nanowires, cantilevers, nanoparticles, nanoshells, dendrimers, fullerenes, micelles and vesicles. Nanotechnology can even be used in the future to treat lifethreatening diseases like cancer. However, it does have some drawbacks, for example, toxicity, environmental harm and organ damage caused by nanoparticles. There are some ethical issues concerned with the use of nanotechnology too. The purpose of the article is to discuss briefly both sides of the field of nanomedicine: to study the applications of nanotechnology in medicine and, also, to discuss its limitations.