The most important legislative function performed by ICAO is the formulation and adoption of Standards and Recommended Practices (SARPs) for international civil aviation. These are incorporated into the 19 technical annexes to the Convention on International Civil Aviation, also known as the Chicago Convention.

Of critical importance to the future of civil aviation and to the international community at large are the measures taken by ICAO to prevent and suppress all acts of unlawful interference against civil aviation throughout the world. SARPs for international aviation security were first adopted by the ICAO Council in March 1974, and designated as Annex 17 to the Chicago Convention.