The Central Treaty Organization (also referred to as CENTO, originally name was Middle East Treaty Organization or METO, also known as the Baghdad Pact) was adopted in 1955 by Iraq, Turkey, Pakistan, and Iran, as well as Britain. Although American pressure, along with promises of military and economic largesse, were key in the negotiations leading to the agreement, the United States chose not to initially participate as to avoid alienating Arab states with whom it was still attempting to cultivate friendly relations. In 1958 the United States finally joined the alliance. It is generally viewed as one of the least successful of the Cold War alliances. Organizations headquarters was in Baghdad, Iraq.

Modeled after the North Atlantic Treaty Organization it committed the nations to mutual cooperation and protection, as well as non-intervention in each other's affairs. Its goal was to contain the Soviet Union by having a line of strong states along the U.S.S.R's southwestern frontier.

In 1959, Iraq, under its new Republican regime, backed out of the Baghdad Pact. Thus, CENTO was created to replace the now-defunct pact.

The United States had a facility in a member state, Pakistan, for spying on the Soviet Union. Based in Peshawar, Pakistan, Lockheed U-2 spy planes flew reconaissance missions over Soviet airspace. After the U-2 Crisis of 1960, Soviet Premier Nikita Khrushchev warned Pakistan that it had become a target for Soviet nuclear forces.

The Middle East and South Asia became extremely volatile areas during the 1960s with the ongoing Arab-Israeli Conflict and the Indo-Pakistani Wars. The United States and CENTO were unwilling to get involved in either dispute. American support for Israel also damaged relations between the States and the Muslim members. In 1965 and 1971 Pakistan tried unsuccessfully to get assistance in its wars with India through CENTO.

The pact also led the United States to support corrupt and/or unpopular regimes in Iraq, Iran and Pakistan.

Most importantly, the alliance did little to prevent the expansion of Soviet influence to non-member states in the area. Other states in the Middle East felt excluded from CENTO and turned to the Soviets, including Egypt and Syria.

It lasted nominally until the Iranian revolution of 1979. However, in reality, it had been as good as finished after 1974, when Turkey invaded Cyprus, leading the United Kingdom to withdraw forces from there that had been declared to the alliance.