Cardinal Joao Braz de Aviz, 65, and Odilo Pedro Scherer, 63, are among the strongest candidates to be adjudged by the conclave.
Cardinal Aviz, from Mafra, Santa Catarina, is currently prefect of the Congregation for Institutes of Consecrated Life and Societies of Apostolic Life.
Cardinal Scherer holds the powerful position as Archbishop of Sao Paulo, a diocese that has existed since 1745.
Pope Benedict, a German native, has relinquished his papacy after eight years in the role, the first Pope to voluntarily do so since 1294.