There are 183 States that currently have diplomatic relations with the Holy See; on 4 May 2017, diplomatic relations were established with the Republic of the Union of Myanmar, at the level of the Apostolic Nunciature and of the Embassy. The European Union and the Sovereign Military Order of Malta are to be added to the aforementioned States.

There are 89 Embassy Chancelleries based in Rome, including those of the European Union and the Sovereign Military Order of Malta, with the Embassy of South Africa added during the year. The offices of the League of Arab States, the International Organization for Migration and the United Nations High Commission for Refugees are also based in Rome.

In 2017 the following Agreements were signed: on 3 February, the Framework Agreement between the Holy See and the Republic of Congo on relations between the Catholic Church and the State; and on 22 August, the Agreement between the Secretariat of State and the Government of the Russian Federation on visa-free travel for holders of diplomatic passports. Furthermore, on 22 May 2017, the Holy See adhered to the Declaration on the Jurisdictional Immunities of State-Owned Cultural Property, an initiative of the Council of Europe’s Committee of Legal Advisers on Public International Law (CAHDI) to support the recognition of the customary nature of the provisions of the United Nations Convention on the Jurisdictional Immunities of States and of their Property of 2 December 2004 concerning the protection of assets belonging to the historical or artistic heritage of a State on temporary loan to another State. Finally, on 20 September 2017, the Holy See, also in the name and on behalf of the Vatican City State, signed the Treaty on the Prohibition of Nuclear Weapons, adopted on 7 July 2017 at the end of the United Nations Conference aimed at negotiating a legally binding instrument to prohibit nuclear weapons; at the same time, the relative instrument of ratification was delivered.