The United States Army Security Assistance Command (USASAC) – "The Army's Face to the World", implements Army security assistance programs, including Foreign Military Sales (FMS) of defense articles and services to eligible foreign governments. For example, the USASAC helped provide Iraq with weapons and ammunition, including Hellfire missiles after it requested them to respond to the increased violence in the country. The USASAC is also responsible for life cycle management of FMS cases, from pre-letter of request, development, execution and closure. Each sale to overseas customers comprise the same "total package" of quality material, spare parts, training, publications, technical documentation, maintenance support and other services that AMC provides to Army units. The command manages about 4,600 FMS cases valued at more than $134 billion.

In addition, USASAC is responsible for Army security assistance information management and financial policy, and provides logistics guidance to the Army security assistance community. Today, the Command is increasingly responding to support of U.S. government emergency assistance, humanitarian relief, and Operations Other Than War, including United Nations peacekeeping operations. USASAC's motto is "Strength in Cooperation."

Security assistance is a national program administered by the State Department. In conjunction with the White House, Congress, and the Treasury Department, military security assistance programs are executed by the Department of Defense (DOD). Security assistance promotes regional stability, deters aggression, maintains alliances, and disseminates democratic values between the United States and its allies.

In carrying out the Army security assistance mission, USASAC calls on all AMC Life Cycle Management Commands, as well as other Department of Defense agencies and U.S. industry for support. USASAC is responsible for life cycle management of FMS cases, from development to execution, financial management, accounting, and settlement. Each sale of equipment to overseas customers comprises the same "total package" of quality materiel, spare parts, training, publications, technical documentation, maintenance support, and other services that AMC provides to U.S. Army units.

Currently, USASAC is actively engaged in the "train and equip" mission in both Iraq and Afghanistan as well as provides support to 21 coalition partners. It was anticipated that sales in 2008 would exceed $15 billion.

USASAC, which traces its origins to the Army's technical service era, was designated a major subordinate command (MSC) of the U.S. Army Materiel Command in 1975.