St Peter's Square in the Vatican City erupted with cheers and bells ringing as white smoke poured from the chimney above the Sistine Chapel.
The new pope, whose identity is still not known, is expected to appear before them with the next hour.
Your step-by-step guide to electing a new pope.
There are no swing states and no polls - all we can do is to watch the chimney for the smoke and wait for the answer, blowing in the wind.
Cardinals of the Roman Catholic Church are gathering in Rome to elect a new pope. Here are some facts about the Papal conclave.