He was 88, and had survived a serious bout of double pneumonia.
"Dear brothers and sisters, it is with profound sadness I must announce the death of our Holy Father Francis," Cardinal Kevin Farrell announced on the Vatican's TV channel.
"At 7:35 this morning the Bishop of Rome, Francis, returned to the house of the Father."
Francis' death comes a day after the pope had made his first prolonged public appearance since being discharged on March 23 from a 38-day hospital stay for pneumonia.
On Easter Sunday, Francis had entered St. Peter's Square in an open-air popemobile shortly after mid-day, greeting cheering crowds. He had also offered a special blessing for the first time since Christmas.
Leaders across the world were reacting to the pope's death with praise for his efforts to reform the worldwide church and offering condolences to the world's 1.4 billion Catholics.
"He inspired millions, far beyond the Catholic Church, with his humility and love so pure for the less fortunate," said European Commission President Ursula von der Leyen.
Jose Ramos-Horta, the president of East Timor, where Francis had visited in September 2024 as part of the longest foreign trip of his papacy, said the pope "leaves behind a profound legacy of humanity, of justice, of human fraternity".
Jorge Mario Bergoglio was elected pope on March 13, 2013, surprising many church watchers who had seen the Argentine cleric, known for his concern for the poor, as an outsider.
He sought to project simplicity into the grand role and never took possession of the ornate papal apartments in the Apostolic Palace used by his predecessors, saying he preferred to live in a community setting for his "psychological health".
He inherited a church under attack over a child sex abuse scandal and torn by infighting in the Vatican bureaucracy, and was elected with a clear mandate to restore order.
But as his papacy progressed, he faced fierce criticism from conservatives, who accused him of trashing cherished traditions. He also drew the ire of progressives, who felt he should have done much more to reshape the 2,000-year-old church.
While he struggled with internal dissent, Francis became a global superstar, drawing huge crowds on his many foreign travels as he tirelessly promoted interfaith dialogue and peace, taking the side of the marginalised, such as migrants.
Unique in modern times, there were two men wearing white in the Vatican for much of Francis' rule, with his predecessor Benedict opting to continue to live in the Holy See after his shock resignation in 2013 had opened the way for a new pontiff.
Benedict, a hero of the conservative cause, died in December 2022.
Francis appointed nearly 80% of the cardinal electors who will choose the next pope, increasing the possibility that his successor will continue his progressive policies, despite the strong pushback from traditionalists.
