A breeding exemption in breeder’s rights law has not been specified in the patent laws of most countries. Since breeding exemption is not a part of research exemption, this paper argues that it is necessary and feasible to introduce into the patent system a limited breeding exemption. Compared with a comprehensive breeding exemption, a limited breeding exemption impairs patent rights less, conforms to the three-step test in Art. 30 of the TRIPS Agreement and is in the public interest. The liability rule is suggested to be used to facilitate the commercialisation of final varieties.