The election will be held entirely in secret, and all communication with the outside world is strictly forbidden, RT reported.
The 115 cardinals are staying at a residence in Vatican, and will remain there until they decide on a new leader.
A special mass, known as 'For the Election of the Roman Pontiff,' will also be held at St. Peter's Basilica in the Vatican.
The conclave is expected to last for no more than a few days, as the new Pontiff has to be elected before Easter celebrations begin at the end of March.