Under Article 102 of the Charter of the United Nations, every treaty and international agreement entered into by a Member State of the UN shall be registered with and published by the Secretariat. Regulations to give effect to Article 102 were adopted by the General Assembly in 1946 and subsequently modified a number of times. Pursuant to the mandate contained in Article 102, the United Nations Treaty Series (UNTS) was created.

The UN Treaty Series exists today in print and online, as part of the United Nations Treaty Collection (http://treaties.un.org/). The site overview includes definitions of key terms as well as a glossary of terms relating to treaty actions. These resources define terms such as accession and ratification and clarify the distinction between, for example, declarations and memoranda of understanding.

The printed volumes of the United Nations Treaty Series reproduce the text of treaties and international agreements registered or filed and recorded with the Secretariat since 1946 in the authentic treaty language(s), together with translations into English and French, as required. A cumulative index provides access to the volumes by subject, participants and date.

The United Nations Treaty Series Database provides online access to the international instruments published in the United Nations Treaty Series.

When conducting treaty research, bear in mind that there may be a substantial gap between the adoption date and the registration date of a treaty or between the adoption date and the date of entry into force. All treaties in the online system are available in pdf format. Various search modes are offered, including:

• Popular Name Search
• Title Search (exact phrase)
• Participant Search
• Advanced Search
• Full-text Search
• Actions Search

The 205 volumes of the League of Nations Treaty Series have been made available in the United Nations Treaty Collection website.

The status of multilateral treaties for which the Secretary-General functions as depositary can be researched in printed format or online through the United Nations Treaty Collection. The printed publication, entitled Multilateral Treaties Deposited with the Secretary-General, gives the status as at 31 December of a given year. In addition to ratification information, it also reprints the declarations, reservations and objections which States Parties have lodged with respect to certain instruments. The online version provides the same information with the advantage of being more up-to-date.

In response to requests from UN bodies, the Secretary-General also reports on the status of individual conventions or groups of conventions. Additionally, the Secretariats of some UN bodies issue status documents for the treaties that relate to their work.

Prepared and maintained by the Department of Public Information (DPI), Dag Hammarskjöld Library (DHL) . Comments as well as suggestions for further additions/enhancements may be directed to the Dag Hammarskjöld Library.