Pope Francis says people across the world are expecting "concrete measures" on tackling the sex abuse scandal in the Catholic church.
He's been speaking to religious superiors as he opened a four-day summit at the Vatican.
The summit will focus on how to deal with cases of child sex abuse by members of the clergy.
Around 200 delegates will attend lectures and workshops on preventing assaults, tending to victims and investigating abuse.
The Pope's warning bishops to "listen to the cry of the young who want justice" and "transform this evil" into understanding.
One of the organisers of the summit, Archbishop Charles J Scicluna, quoted a letter from Pope Benedict to the people of Ireland:
Only by examining carefully the many elements that gave rise to the present crisis can a clear-sighted diagnosis of its causes be undertaken and effective remedies be found.
