At his home in London at the age of 41, it has been announced.
Ghana-born Dumor was a presenter for BBC World News and its Focus on Africa programme.
One of Ghana's best-known journalists, he joined the BBC as a radio broadcaster in 2007 after a decade of journalism in Ghana.
Ghanaian President John Dramani Mahama said on Twitter that his country had lost one of its finest ambassadors.
BBC Global News Director Peter Horrocks called Dumor a leading light of African journalism who would be deeply missed.
New African magazine
November 2013
He was "committed to telling the story of Africa as it really is," Mr Horrocks said in a statement.
"Africa's energy and enthusiasm seemed to shine through every story Komla told".
"Komla's many friends and colleagues across Africa and the world will be as devastated as we are by this shocking news."
The BBC understands he had suffered a heart attack.
Komla Dumor featured in New African magazine's November 2013
list of 100 most influential Africans. It said he had "established
himself as one of the emerging African faces of global broadcasting",
who had "considerable influence on how the continent is covered".
James Harding, BBC Director of News and Current Affairs,
spoke of Komla Dumor's "singular role in transforming the coverage of
Africa". "He brought a depth of understanding, a great deal of courage, a
joyous charm and boundless charisma to his work," Mr Harding said.
Komla Dumor had a wide-ranging career as an interviewer and presenter
Komla Dumor was born on 3 October 1972 in Accra, Ghana.
He graduated with a BA in Sociology and Psychology from the
University of Ghana, and a Masters in Public Administration from Harvard
University.
He won the Ghana Journalist of the Year award in 2003 and joined the BBC four years later.
From then until 2009 he hosted Network Africa for BBC World Service radio, before joining The World Today programme.
Komla Dumor presenting Africa Business Report in 2009
In 2009 Komla Dumor became the first host of Africa Business
Report on BBC World News. He was a regular presenter of Focus on Africa
and had fronted the programme the day before he died.
He travelled across Africa, meeting the continent's top
entrepreneurs and reporting on the latest business trends around the
continent.
He interviewed a number of high-profile guests including Bill Gates and Kofi Annan.
Last month, he covered the funeral of former South African
President, Nelson Mandela, whom he described as "one of the greatest
figures of modern history".
He anchored live coverage of major events including the 2010
World Cup in South Africa, the funeral of Kim Jong-il, the release of
Israeli soldier Gilad Shalit, the Norway shootings and the wedding of
Prince William and Kate Middleton.
In his review of 2013, published last month, Dumor said the passing of Mandela was "one of the moments that will stay with me".
"Covering the funeral for me will always be a special moment.
I will look back on it with a sense of sadness. But also with
gratitude. I feel lucky to have been a witness to that part of the
Mandela story."
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