Bookmakers think the next Pope could come from Africa, following the resignation of Benedict XVI.
Up to 120 cardinals from all over the world will vote on who will succeed 85-year-old Benedict, who is standing down for health reasons.
Nigeria's Cardinal Francis Arinze and Cardinal Peter Turkson from Ghana are the front-runners with William Hill and Ladbrokes respectively.
Arinze, seen as a staunch conservative on issues like birth control, was a hot favourite for the post last time around and is the 2/1 favourite with William Hill.
Turkson, the 5/2 favourite with Ladbrokes, is president of the Vatican's council for justice and peace and has also been linked with the top job. Last year he was embroiled in a row over an 'anti-Muslim' video.
Other contenders include Honduran Oscar Rodriguez Maradiaga, who is 20/1 with William Hill and 10/1 with Ladbrokes.
Meanwhile, Englishman Cardinal Cormac Murphy-O’Connor is 150/1, according to comparison site Odds Checker.
Despite the Ghanaian and Nigerian front-runners, Paddy Power believes the next pontiff is most likely to come from Italy, followed by Africa and South or Central America.