Forty-five years after the signature of the Antarctic Treaty, the Antarctic Treaty Consultative Meeting XXVI in Madrid established the Secretariat of the Antarctic Treaty with its Measure 1 (2003). The Secretariat went into operation on 1 September 2004. Consultative Parties to the Antarctic Treaty had developed a new concept of a Secretariat. Created under the Antarctic Treaty, the Antarctic Treaty Consultative Meeting does not have an international legal personality. As a consequence, the Secretariat was founded as an entity under Argentine law and was internationally privileged through a headquarters agreement between the Consultative Parties and the government of Argentina. Patrizia Vigini published an analysis of the Secretariat after three years of its operation. This paper analyzes the performance of the Secretariat eleven years later. In doing so, it follows the requirements described in Measure 1 (2003). After 14 years of operation the Secretariat enjoys a stable position of operation and successfully supports the work of Antarctic Treaty Consultative Meetings and the Committee for Environmental Protection. It can be considered as an essential improvement to the functioning of the Antarctic Treaty System.