The recent practice of the Swiss cantons in international matters is relatively poorly known. The purpose of this compendium is to fill this gap and thus measure in its concrete data a problem typically raised in terms of principles. It brings together the cantonal treaties in force on 1 January 1980. It does not include border treaties and outdated conventions. On the other hand, agreements whose imputability is uncertain or whether it is subject to the law of people in doubt were retained. The texts reproduced are accompanied by information collected by the author from the Federal Department of Foreign Affairs and the cantonal administrations concerned.