Published on 1 February 2026

Depositary

Switzerland is the depositary state for 75 international treaties.

Functions of the depositary

The functions of the depositary are in principle limited to the reception, formal review, transmission and storage of communications and acts of current or future States parties. The depositary may also control the compliance with the formal requirements that States have to meet about a particular act. E.g. it can return an instrument of accession which is not signed by a person duly authorized under international law. It can also control in each case whether the conditions for accession to a treaty are effectively met.

However, it is not for the depositary to exercise a substantive control over the acts submitted to it. This competency lies exclusively with the States Parties. E.g. the control of the substantive admissibility of reservations to a treaty lies in the exclusive competence of the States parties.

When it comes to wearing a material judgment on any particular treaty action, the depositary that would be simultaneously a State party has to distinguish its role as depositary from its position as State party. The depositary is required to act impartially in the performance of its functions (see art. 76–80 of the 1969 Vienna Convention on the Law of Treaties).

The detailed pages on depositary treaties are available in French only, but contain the notifications and treaty texts in all original languages. For each treaty, the following information is provided: original texts, list of Contracting Parties, reservations and declarations, depositary notifications.

Depositary