Majid had been convicted of 13 counts of killings and genocide and sentenced to death in four separate trials, including one that centered on his involvement in a poison gas attack that killed about 5,000 people.
His execution was announced by Iraqi government officials, KUNA, the Kuwait news agency reported.
The 1988 gas attack on Halabja earned Majid his nickname. Majid was convicted by the Iraqi High Tribunal of ordering jets to fly over Halabja and spray mustard gas and nerve agents. Majid also had been convicted of killing Shiite Muslims.
Majid was arrested in August 2003, five months after the U.S.-led invasion of Iraq.