Iraq actively researched weapons of mass destruction (WMD) and used chemical weapons from 1962 to 1991, after which it destroyed its chemical weapons stockpile and halted its biological and nuclear weapon programs as required by the United Nations Security Council. Iraqi president Saddam Hussein was internationally condemned for his use of chemical weapons against Kurdish civilians and military targets during the Iran–Iraq War. Saddam pursued an extensive biological weapons program and a nuclear weapons program, though no nuclear bomb was built. After the Gulf War, UN inspectors located and destroyed large quantities of Iraqi chemical weapons and related equipment and materials; Iraq ceased its chemical, biological and nuclear programs.

In the early 2000s, U.S. president George W. Bush and British prime minister Tony Blair both falsely asserted that Saddam's weapons programs were still active and large stockpiles of WMD were hidden in Iraq. Inspections by the UN to resolve the status of unresolved disarmament questions restarted between November 2002 and March 2003, under United Nations Security Council Resolution 1441, which demanded Hussein provide "immediate, unconditional and active cooperation" to UN and IAEA inspections. The United States asserted that Hussein's lack of cooperation was a breach of Resolution 1441, but failed to convince the United Nations Security Council to pass a new resolution authorizing the use of force. Despite this, Bush asserted peaceful measures could not disarm Iraq and launched the Iraq War. A year later, the U.S. Senate released its Report of Pre-war Intelligence on Iraq which concluded that many of the pre-war statements about Iraqi WMD were not supported by the underlying intelligence.

U.S.-led inspections later found that Iraq had ceased active WMD production and stockpiling. Some have argued the false WMD allegations were used as a deliberate pretext for war. After the failure to find WMD stockpiles, some conjectures were put forward, without substantial evidence, that the weapons might have been hidden or sent elsewhere. In July 2004, official U.S. and British reports concluded that spy agencies had "listened to unreliable sources," leading to "false or exaggerated allegations about an Iraqi arsenal." The WMD intelligence errors spurred the U.S. Intelligence Community to develop "new standards for analysis and oversight."

Iraq signed the Geneva Protocol in 1931, the Nuclear Non-Proliferation Treaty in 1969, and the Biological Weapons Convention in 1972 but did not ratify it until June 11, 1991. Iraq ratified the Chemical Weapons Convention in January 2009, with its entry into force for Iraq coming a month later on February 12.

1959 – August 17 USSR and Iraq signed an agreement for the USSR to build a nuclear power plant and established a nuclear program as part of their mutual understanding.

1968 – a Soviet supplied IRT-2000 research reactor together with a number of other facilities that could be used for radioisotope production was built close to Baghdad.

1975 – Saddam Hussein arrived in Moscow and asked about building an advanced model of an atomic power station. Moscow would approve only if the station was regulated by the International Atomic Energy Agency, but Iraq refused. However, an agreement of co-operation was signed on April 15, which superseded the one of 1959.

After 6 months France agreed to sell 72 kg of 93% uranium and built a nuclear power plant without IAEA control at a price of $3 billion.