Ghanaian diplomat, who served as seventh secretary general of United Nations between 1997 and 2006, dies aged 80
He "passed away peacefully on Saturday after a short illness", the foundation named after him said on Saturday.
Annan was the first black African to take up the role of the world's top diplomat, serving from 1997 to 2006.
He later served as the UN special envoy for Syria, leading efforts to find a peaceful solution to the conflict.
In a statement announcing his death, the Kofi Annan Foundation described him as a "global statesman and deeply committed internationalist who fought throughout his life for a fairer and more peaceful world".
"Wherever there was suffering or need, he reached out and touched many people with his deep compassion and empathy. He selflessly placed others first, radiating genuine kindness, warmth and brilliance in all he did."
The diplomat, who was originally from Ghana, died in the Swiss city of Geneva, where he had been living for several years.