While in the Act of 1991 of the UPOV Convention the Farm-Saved Seed (FSS) is expressly codified and further developed, this provision is missing from the previous Acts. The literature argues that the FSS is admissible under the Acts of 1961 and 1978, but very little guidance is provided by the Union on its interpretation under those Acts. The current study addresses the delimitation of the scope of the FSS under the Acts of 1961 and 1978. To this purpose, the role of the main potentially applicable means of interpretation of the Convention have been thoroughly analyzed. From the results of this analysis, the scope of the FSS under the relevant Acts has been determined. The study concludes that the FSS has been expressly accepted by the Union since its very beginning, in the Diplomatic Conferences of 1957-1961. However, its scope, already under the earlier Acts, is not unlimited. Besides, a clear trend towards its restriction has been appreciated, not only between the Acts of 1991 and the previous ones,(4) but also between the means of interpretation of the Act of 1961 and those means applicable to the interpretation of the Act of 1978. The interest of these and other findings of the study is not restricted though to the interpretation of the FSS under the earlier UPOV Acts. This study may also play a key role in the interpretation of the FSS under the Act of 1991, and help to better design the future of sui generis systems for plant variety protection.