President Oscar Arias says forbidding priests from sexual relations goes against nature and the church should "correct that error."
Arias also said Wednesday he supports a proposal being discussed by lawmakers in his Central American nation to grant some civic rights to same-sex couples.
He says "sexual orientation is given by God or by nature" and urges his countrymen to respect homosexuals.
Arias won the Nobel Peace Prize for mediating in Central American conflicts. He leaves the presidency in May, when the first woman elected president in Costa Rica will replace him.