The procedure following the death of the Pope was revised by the Vatican in February 1996. The new document (Universi Dominici Gregis, "The shepherd of the Lord's whole flock") replaces the previous instruction of 1975 from Pope Paul VI.

The Chamberlain (Camerlengo) of the Holy Roman Church is the one who ascertains the Pope's death in the presence of the Papal Master of Ceremonies and a number of other members of the Papal Household. He notifies the Cardinal Vicar for Rome who in turn notifies the people of Rome. The Chamberlain seals the Pope's apartments and begins to make arrangements for the burial. It is the Dean's responsibility to inform the Diplomatic Corps and Heads of state.

Nine days of official mourning are declared and burial takes place between the fourth and sixth day after death (except for special reasons). Popes are usually buried in St Peter's Basilica, where the body will be laid in state for people to pay their respects.

All heads of departments (including the Secretary of State and Prefects of Congregations) cease to exercise their office and the day-to-day running of the Church is done by the College of Cardinals, called together by the Dean. The routine business of departments is looked after by their Secretaries. Important decisions are taken by the College of Cardinals, but they have no power to take decisions that would normally be left to the Pope himself. One of the most important priorities is preparation for the election of the new Pope.

One of the changes made in the 1996 document concerns the conclave. The word itself comes from the Latin cum clave (literally "with a key") and meant that the cardinals were locked in the Apostolic Palace until they produced a result. Now the Cardinals are to be housed in a new building inside the Vatican's walls called the Domus Sanctae Marthae (St Martha's House) and move from there to the Papal Palace and the Sistine Chapel for the actual voting process. While they are moving to and from their new accommodation they are forbidden to communicate with anyone not involved in the election.

Since 1059 the election of the Pope has been reserved to the cardinals alone and this is their principal function - this is the first thing said about them in the Church's Code of Canon Law. Cardinals are not an 'order' in the Church like bishops or priests and so they are not ordained as cardinals, simply appointed by the Pope. From time to time the Pope calls a meeting of cardinals called a 'Consistory' and announces the names of new cardinals. The creation of new cardinals ensures that there is a sufficient number eligible to vote (i.e. under the age of 80) up to a maximum of 120.

The cardinals were originally a group of clergy who were around the Pope to advise him. By the 12th century the cardinals consisted of 7 bishops of dioceses round Rome, 28 priests from Roman churches and 20 deacons. Cardinals are still ranked as cardinal bishops, cardinal priests and cardinal deacons, even though now (since 1962) they are all required to be bishops before they are made cardinal.

15 days after the pope's death (and not later than 20 days) the election begins with a mass in St Peter's celebrated by all the cardinals. That afternoon the cardinals proceed to the Sistine Chapel, where voting has traditionally taken place beneath Michelangelo's fresco of the Last Judgement. The revised rules make no mention of the tradition of the white smoke that signals the end of voting and election of a new Pope. Even though they are no longer locked in, the process is still referred to as a 'conclave' and the process is made as private and secret as possible, even to the extent of ensuring that an electronic sweep is done in the chapel to detect any 'bugs' planted.

The cardinals take an oath promising secrecy and the order is given, Extra omnes ("all outside"). The oath of secrecy forbids them to communicate with anyone not involved in the election, or even to disclose details of the votes when the election is over.

Traditionally, there were three methods of choosing the new Pope. The first was by acclamation, when all the cardinals agreed to one name proposed, without prior arrangement. This, however, appears never to have happened. The second was by compromise, when a stalemate was resolved in one of three ways - - a simple majority, plus one - a ballot between the two strongest candidates - delegating the election to a small group of between 9 and 15.

Now there is only one method, a simple two-thirds majority (or two thirds plus one if the number is not exactly divisible). [N.B. See the section 'Resolving deadlock' below]

Voting begins on the first day, when one ballot is held in the afternoon if possible. If the first ballot does not produce a result, there are two ballots each morning and each afternoon until a result is declared.

The Papal Master of Ceremonies hands out voting papers, giving at least two or three to each cardinal. Nine cardinals are chosen by lot for three tasks: three are to be scrutineers, three are to collect the votes of those who are sick and unable to be in the Sistine Chapel but who are nonetheless able to vote, and three are to double-check the counting. The ballot paper is divided in two: the top half carries the words "Eligo in Summum Pontificem" (I elect as pope...) and the bottom half is blank for the name to be written in. The handwriting on the bottom part should not be identifiable as belonging to any cardinal, and the inclusion of a second name will render the ballot null and void. The Master of Ceremonies and others leave, the doors of the Sistine Chapel are closed and the vote begins. In order of precedence, each cardinal elector holds up his completed ballot paper. He then carries it to the altar and places it in a receptacle. He swears that his vote is for his choice and puts the paper onto a plate, which he uses then to drop the voting slip into the receptacle on the altar.

When all votes have been placed in the urn (including the votes of any sick cardinals whose votes have been collected from the Domus Sanctae Marthae), the urn is shaken. A scrutineer takes the votes out one by one, in full view, and puts them into another container, making sure that the number of slips corresponds to the number of voters. If not, the ballot is void.

The scrutineers sit at a table in front of the altar. The first scrutineer unfolds each paper, notes the name and passes it to the second, who does the same. The third then reads out the name that has been written down and the electors can make note of the names and votes. The scrutineers write down the number of votes received by each name and the last scrutineer collects the voting slips by threading a needle through the word Eligo and collecting the slips on a thread which is then knotted. (The slips are burned at the end of the session, together with any notes the electors have made.) The names are counted and if a name has received two-thirds of the votes, the pope has been elected. The counting is checked by the third group of three cardinals (the 'revisers') who examine both the original voting slips and the scrutineers' notes. The Chamberlain records the votes in each ballot on one sheet of paper and after the election this is given to the new pope before it is stored in a confidential archive.

If the first ballot does not produce a result, the process is repeated for three days only. After three days of unsuccessful voting, the procedure is suspended for a day to give time for prayer, reflection and informal discussions. The voting then begins again for a series of seven more ballots. If there is still no conclusion, another pause is taken before a further seven ballots. If this still does not produce a result, one more pause and another series of seven ballots follow. Finally, however, the cardinals are addressed by the Chamberlain about what to do next.

The election goes forward in the way that the majority of electors decide. A result can now come from an absolute majority or by a vote on the two names that received the largest number of votes in the last ballot. Here, too, an absolute majority is required.

The successful candidate is then asked by the Dean of the College of Cardinals, "Do you accept your canonical election as Supreme Pontiff?" When he gives his agreement, he is then asked what name he will choose as Pope. This agreement and choice is then signed and (assuming that the person is already a bishop) he is immediately Bishop of Rome. The cardinals pay him their respects and the Cardinal Deacon announces the result of the election to the people in St. Peter's Square. The new Pope comes out and gives them his blessing. There is no longer a coronation ceremony, but the Pontificate is inaugurated at a ceremony in St Peter's a short time later.