Nanotechnology uses a basic unit of measure called a “nanometre” (nm). It is one-billionth of a metre. Nanotechnology is a very vast field, which includes a range of nanoscale technologies, such as pharmaceutical sciences, biotechnology, genomics, neuroscience, robotics, information technologies, etc. In the 1990s there was a significant growth in the number of nanotechnological patents. Patenting nanotechnological inventions is not the same as that of other technologies as there are some problems with patent requirements. The difficulties concern fulfilling patentability criteria for novelty, inventiveness and industrial applications. The lack of a standardized definition of nanomaterials has implications for patent search and classification. The aim of this article is to analyse the main problems with patenting nanotechnological inventions.