He plans to take a break from campaigning to speak at a special Vatican conference discussing social, economic and environmental issues.
The Vermont senator will head to Rome following his public debate with rival Hillary Clinton.
Mr Sanders is a fan of Pope Francis and has often quoted him, saying he is "speaking out with courage and brilliance about some of the most important issues facing our world," according to the New York Times.
He is flying to Rome to talk at the Pontifical Academy of Social Sciences.
Bishop Marcelo Sánchez Sorondo, the chancellor, said: "We invited the candidate who cites the pope the most in his campaign, and that is Senator Bernie Sanders."
Msgr Sánchez Sorondo added that Bernie Sanders focussed on climate change and people on the margins of society.
The Vatican conference also celebrates the 25th anniversary of an encyclical by Pope John Paul II about the potential pitfalls of the market economy after the fall of the Berlin Wall.
Much rhetoric has surrounded whether Mr Sanders asked for an audience with the pope.
Vatican spokesperson Revd Federico Lombardi said: "There won't be a meeting with the Holy Father."
He added that the pope would be in Lesbos on Friday and would not be there when Mr Sanders would arrive and has stressed that an invite to visit the Vatican is not the same as an audience with the pope.
