Iran's president Hassan Rouhani asked Pope Francis to pray for him at the end of their audience in the Vatican on Tuesday.
"I ask you to pray for me," Rouhani said.
"The visit pleased me a lot. I wish you well in your work", Rouhani added, according to those present.
Inter-faith dialogue and Iran's key role in Middle East peace and in fighting terrorism and arms trafficking in the fraught region were the focus of Rouhani's talks with Francis, the Vatican said in a statement.
Rouhani was the first Iranian president received by a pope since reformist president Mohammad Khatami's audience with John-Paul II in 1999.
He is on the first visit to Europe by an Iranian president in 16 years.