Dozens of cardinals are eligible to become the next pope, but only a few are considered pontiff material, or "papabile".
The successor to Benedict XVI, who resigns on Thursday, will be elected by a conclave in the Sistine Chapel next month where 115 cardinals from around the world are expected.
Following are some of the top contenders to become the next head of the world's 1.2 billion Catholics:
The 72-year-old archbishop of Milan is the top Italian candidate. He is a keen promoter of inter-religious dialogue, particularly between Muslims and Christians.
He is also an expert on bioethics, an issue on which Church teachings are currently lagging behind scientific advances.
Archbishop of Budapest since 2002 and a specialist in canon law who has taught at the Pontifical Lateran University in Rome, the 60-year-old Hungarian is tipped as another European frontrunner.
The archbishop of Vienna, 68, is a protege of outgoing Benedict XVI and was a favourite for future pope before he called in 2010 for a re-examination of the contentious issue of priest celibacy in the wake of the child sex abuse scandal.
He has also criticised powerful figures in the Vatican for covering up the sex crimes.
Keeping the St. Peter's chair in the hands of Europeans would help ensure the future of the Church in the increasingly secularised continent.
LUIS ANTONIO TAGLE
The archbishop of Manila was last year appointed the Church's second youngest cardinal. The 55-year-old is tipped as an outsider to watch for his dynamism, charisma and stellar rise within the Church so far.
His relative youth stands against him, but he is very popular in Asia and has worked closely with Benedict.
Canada's former archbishop of Quebec, 67, Ouellet now heads the influential Congregation of Bishops.
Known for his conservative theological views -- very much in line with Benedict's -- Ouellet could be favoured for the pull he may have in the increasingly secularised West. Supporters hope he would also crack down on the unruly curia, the Vatican's government. He is the head of the Pontifical Commission for Latin America, where has a strong following.
Archbishop of New York and a "modernist conservative", 63-year old Dolan is media savvy -- a plus in today's social media society.
Vatican observers say his strong point lies in heading up a diocese which has been on the front-line in the damaging sex abuse scandal which had rocked the Church, but he has been heavily criticised by abuse victims group for allegedly covering up cases.
The head of the Vatican's Pontifical Council for Justice and Peace, the 64-year-old Ghanaian is leading the race to become the Vatican's first African pope.
He is considered progressive by supporters but his decision to show a recent synod a video criticising Muslims has damaged his chances according to some, who accuse him of lacking key interreligious sensibilities.
Others tipped are Laurent Monsengwo Pasinya, the 74-year-old Archbishop of Kinshasa in Congo, and Nigerian John Onaiyekan, the 69-year-old Archbishop of Abuja who promotes dialogue with Muslims.
The 63-year-old archbishop of Sao Paolo, home to five million faithful in a country that boasts the world's largest Catholic population, is Latin America's best hope. Scherer is seen as a moderate conservative with charisma and openness, as well as a good administrator.
The Brazilian of German origin has fought against declining traditional values and is concerned about the growing strength of evangelical churches.
Brazil alone will be represented by five cardinals in the conclave.