The Full Form of CENTRO is‍ Central Treaty Organization.

The Baghdad Pact was a defensive organization for promoting shared political, military and economic goals founded in 1955 by Turkey, Iraq, Great Britain, Pakistan and Iran. Similar to the North Atlantic Treaty Organization and the Southeast Asia Treaty Organization, the main purpose of the Baghdad Pact was to prevent communist incursions and foster peace in the Middle East. It was renamed the Central Treaty Organization, or CENTO, in 1959 after Iraq pulled out of the Pact.

In the early 1950s, the United States Government expressed an interest in the formation of a Middle East Command to protect the region against communist encroachment. The nature of some of the ongoing tensions in the region, like Arab-Israeli conflict and Egyptian-led anti-colonialism, made it difficult to forge an alliance that would include both Israel and Western colonial powers. Instead, the U.S shifted its focus to the “Northern Tier,” referring to the line of countries that formed a border between the U.S.S.R. and the Middle East. The idea was to conclude an alliance that would link the southernmost member of the North Atlantic Treaty Organization (NATO), Turkey, with the westernmost member of the Southeast Asia Treaty Organization (SEATO), Pakistan. Turkey and Pakistan signed an agreement in 1954 to increase security and stability in the region. In February 1955, Iraq and Turkey signed a “pact of mutual cooperation” in Baghdad to resist outside aggression, and they opened it to other countries in the region as well. In April, the United Kingdom announced its intention to adhere to the Pact, and it was followed by Pakistan and finally, Iran. The King of Jordan considered joining, but he could not overcome domestic opposition to the pact. The United States signed individual agreements with each of the nations in the Pact, but it did not formally join. Instead, the United States participated as an observer and took part in committee meetings.

Developments in the Middle East in the years that followed weakened the Pact. In 1956, Egyptian leader Gamal Abdel Nasser seized control of the Suez Canal, an important international waterway. Israel responded by invading the Sinai peninsula, and British and French forces intervened. The outcome of the incident was a profound loss of British prestige in the region, which in turn damaged its position of leadership in the Baghdad Pact. A series of events in 1958, including an Egyptian-Syrian union, an Iraqi revolution, and civil unrest in Lebanon threatened regional stability. In response to these developments, the United States invoked the 1957 Eisenhower Doctrine as justification for intervening in Lebanon. The members of the Baghdad Pact except for Iraq endorsed the U.S. intervention, and in 1959, Iraq announced it was formally leaving the arrangement. As a result, the other signatories to the Baghdad Pact formed the Central Treaty Organization, or CENTO. Although the United States was still not a member of the organization, it did sign bilateral military aid treaties with Pakistan, Iran and Turkey, ensuring that it would continue to be active in supporting the CENTO members.

CENTO never actually provided its members with a means for guaranteeing collective defense. After the withdrawal of Iraq from the Baghdad Pact, CENTO moved its headquarters to Ankara, Turkey, and the United States continued to support the organization as an associate, but not as a member. CENTO never created a permanent military command structure or armed forces, but the United States provided assistance to its allies in the region. By the close of the Eisenhower Administration, it had become clear to CENTO members that that the organization was a better conduit for economic and technical cooperation than it was a military alliance. In 1979, the Iranian revolution led to the overthrow of the shah and Iran’s withdrawal from CENTO. Pakistan also withdrew that year after determining the organization no longer had a role to play in bolstering its security. CENTO formally disbanded in 1979.