He fell ill on Friday while meeting US Secretary of State Hillary Clinton.
He was President Barack Obama's special envoy to Afghanistan and Pakistan. The presidents of both nations had called to wish him well prior to his death.
Mr Obama called the 69-year-old, who was known for bringing warring leaders to the negotiating table, a "true giant of American foreign policy".
Mr Holbrooke was meeting Ms Clinton at the US state department on Friday morning when he collapsed.
He was rushed to the US capital's George Washington University Hospital, where he underwent surgery to repair a tear in his aorta, the largest artery in the human body, which carries oxygenated blood from the heart.
Mr Holbrooke's death comes as the Obama administration prepares to make public its latest review of US policy in Afghanistan and Pakistan.
Following the news, Mr Obama said: "Richard Holbrooke (was] a true giant of American foreign policy who has made America stronger, safer and more respected."
EU delay for Palestinians
Foreign ministers from the European Union have said they would recognise a Palestinian state "when appropriate".
The ministers' statement followed a call from Palestinian leader Mahmoud Abbas for the EU to recognise Palestine based on the 1967 borders.
Oprah is a hit Down Under
US chat show host Oprah Winfrey has taped two shows for her 25th and final series in front of thousands of screaming fans in Sydney, Australia.
The shows were taped next to the city's landmark opera house, re-named the "Oprah House" for the occasion.
She justified Australia spending about $5m (3m) to bring her there, saying the shows will be worth millions more in tourism publicity.
Oprah also brought over 300 US audience members with her.
South Korean army chief quits
The head of South Korea's army, General Hwang Eui-don, has resigned, officials at the defence ministry have said.
The reasons have not been given, but he had faced criticism over capital gains he made through a Seoul property deal. It comes amid rising tensions over North Korea's shelling of a Southern island.
Paltrow joins Walk of Fame
Oscar-winner Gwyneth Paltrow has been honoured with a star on the Hollywood Walk of Fame.
Country singers Faith Hill and Tim McGraw helped Paltrow celebrate the unveiling. It comes in advance of the release of her new film, Country Strong, co-starring McGraw.
Berlusconi makes plea ahead of vote
Italy: Prime minister Silvio Berlusconi has urged MPs not to jeopardise the government as he faces two crucial confidence votes.
He told the Senate that Italy needed continuity, and the lower house he would be willing to welcome rebel centre-right deputies back to his government.
Africa: Aid groups have called for efforts to prevent mass killings by rebel militias the Lord's Resistance Army over the Christmas period.