"The United States has conducted an operation that killed Osama bin Laden, the leader of al Qaeda and a terrorist who is responsible for the murder of thousands of men, women and children," Obama said.
It is a major accomplishment for Obama and his national security team, after many Americans had given up hope of ever finding bin Laden.
A crowd gathered outside the White House to celebrate, chanting, "USA, USA."
Obama's predecessor, George W. Bush, had repeatedly vowed to bring bin Laden to justice "dead or alive" for the September 11, 2001, attacks on New York and Washington that killed nearly 3,000 people, but never did before leaving office in early 2009.
U.S. officials said that after searching in vain for the al Qaeda leader since he disappeared in Afghanistan in late 2001, the Saudi-born extremist was killed in the Pakistani town of Abbotabad and his body recovered.