Nanotechnologies are an expression of the human ability to control and manipulate matter on a very small scale. Their use will enable an even and constant monitoring of human organisms, in a new and perhaps less invasive way. Debates at all levels – national, European and international – have pointed out the common difficulty of giving a complete, clear definition of nanotechnologies. This is primarily due to the variety of their components, to the fact that there is not just one technology but several. The most significant medical applications of nanotechnologies are in the diagnostic and the therapeutic fields, eg biosensors and molecular imaging, providing diagnosis and drug delivery with no invasive methods involved. Like any other emerging field, such technologies imply new possibilities for improving health but, on the other hand, they are still at an experimental stage and therefore should be implemented under rigorous safety testing before going on general release. For this purpose, the ethical, legal and social implications (ELSI) of nanotechnologies have been elaborated by study groups, in order to develop solutions before the results of the tests are diffused into medical practice. The aim of this paper is to define some of the ethical issues concerning biomedical applications and to evaluate whether there is a need for new or additional guidelines and regulations.