The paper examines, first, the exclusion of patent protection for plants, including plant varieties, biological materials, and essentially biological processes for the production of plants. The legal implications of the right – recognized under the TRIPS Agreement – to exclude plants from patent protection are briefly discussed, as well as how the exclusion allowed by article 27.3(b) of said Agreement has been implemented at the national level and, particularly, whether it can be extended to parts and components of plants.