Pope Benedict XVI celebrated Mass before a crowd of a million people in Sao Paulo, at which he canonised Brazil's first native-born saint.
The faithful, gathered from across Latin America, cheered and waved images of the Pope at Sao Paulo's Campo de Marte airfield. Many had spent the night there.
The 80-year-old pontiff announced the sainthood from a wooden throne flanked by bishops and choirs, and overlooked by a giant wooden crucifix.
The new saint, the 18th Century Franciscan monk, Friar Antonio Galvao, founded monasteries and convents throughout the country.
The Pope lauded Friar Galvao as a model of rectitude and humility and criticised sectors of the global media which he said glorified promiscuous sex and hedonism.
He then invited to the altar a mother and her seven-year-old son, whose birth is considered to be one of the two miracles attributed to the newly declared saint.
Correspondents say the Church in Brazil hopes the Pope's visit and the canonisation will help reinvigorate the local church, which has lost millions of faithful to evangelical churches.