He had been admitted to hospital in February for bronchitis treatment.
Pope Francis has died at the age of 88.
He appeared in public, just yesterday, greeting crowds on Easter Sunday.
The pontiff became Pope in 2013 after the resignation of his predecessor Benedict XVI.
In a statement, the Vatican said, "Dearest brothers and sisters, with deep sorrow I must announce the death of our Holy Father Francis.
"At 7.35am this morning [local time], the Bishop of Rome, Francis, returned to the house of the Father. His entire life was dedicated to the service of the Lord and His Church.
"He taught us to live the values of the Gospel with fidelity, courage and universal love, especially in favour of the poorest and most marginalised.
"With immense gratitude for his example as a true disciple of the Lord Jesus, we commend the soul of Pope Francis to the infinite merciful love of the One and Triune God."
The arrangement for Pope Francis's funeral are happening, while the Papal Conclave is due to meet over the next few weeks to start the process of electing a new pope.
President Michael D Higgins and Pope Francis at Áras an Uachtaráin.Ireland
During his papacy he visited Ireland - the first time a Pope had come here in almost 40 years - and visited Croke Park, Knock Shrine, Áras an Uachtaráin
and attended a mass in the Phoenix Park with around 150,000 others.
He visited a very different Ireland to his predecessor John Paul the second - having since voted in referenda for divorce, marriage equality and repealing the eighth amendment.
His two day trip here was overshadowed by sexual and institutional abuse.
During a speech in Dublin - he also said he understood why people in Ireland were disillusioned with the church.
The Tánaiste and Taoiseach are among those paying tribute to the Pontiff.
