The pontiff was speaking to a group of bishops at the Italian Bishops Conference on Tuesday about issues in the Catholic Church.
He said the bishops should not hesitate to voice their opinions about what the Church is doing wrong.
"It is not a sin to criticise the pope here. It is not a sin, it can be done," Pope Francis said.
During his speech, the pope listed a decline in vocations, financial scandals and the need to reduce the number of dioceses, as major concerns he has for the Church.
Stay up to date with the latest news stories from a Christian perspective. Sign up to our daily newsletter and receive more stories like this straight to your inbox every morning.