The United Nations Secretariat is one of the principal organs of the United Nations and it is headed by the United Nations Secretary-General, assisted by a staff of international civil servants worldwide. It provides studies, information, and facilities needed by United Nations bodies for their meetings. It also carries out tasks as directed by the UN Security Council, the UN General Assembly, the UN Economic and Social Council, and other U.N. bodies. The United Nations Charter provides that the staff be chosen by application of the "highest standards of efficiency, competence, and integrity," with due regard for the importance of recruiting on a wide geographical basis.

The Charter provides that the staff shall not seek or receive instructions from any authority other than the UN. Each UN member country is enjoined to respect the international character of the Secretariat and not seek to influence its staff. The Secretary-General alone is responsible for staff selection.

The Secretary-General's duties include helping resolve international disputes, administering peacekeeping operations, organizing international conferences, gathering information on the implementation of Security Council decisions, and consulting with member governments regarding various initiatives. Key Secretariat offices in this area include the Office of the Coordinator of Humanitarian Affairs and the Department of Peacekeeping Operations. The Secretary-General may bring to the attention of the Security Council any matter that, in his or her opinion, may threaten international peace and security.

On 21 March 2005, Secretary-General Kofi Annan proposed several reforms for the Secretariat. He announced his intentions to appoint a Scientific Adviser, create a peacebuilding support office, establish a cabinet-style decision-making mechanism, and strengthen the mediation function. He also asked the General Assembly to appropriate funds for a one-time staff buyout; to work with him in revising budgetary and human resources rules; to grant the Secretary-General more managerial authority and flexibility; to strengthen the Office of Internal Oversight Services; and "to review all mandates older than five years to see whether the activities concerned are still genuinely needed or whether the resources assigned to them can be reallocated in response to new and emerging challenges" http://www.un.org/largerfreedom/chap5.htm.