Twenty Vice-Presidents are elected annually at the beginning of an ordinary session and remain in office until the opening of the next session (but a Vice-President whose delegation is renewed in the course of a session does not remain in office). The number of Vice-Presidents has been increased on several occasions as the number of member States has grown.
To ensure an equitable division of Vice-Presidents between different sized national delegations, member States are divided into four Groups. Delegations with 18 seats in the Assembly (France, Germany, Italy, Russian Federation, Turkey and the United Kingdom), each have a Vice-President every year; delegations with between 12 and 17 seats (Poland, Spain and Ukraine) have two Vice-Presidents between them, with one change happening each year; delegations with between 5 and 11 seats (Austria, Azerbaijan, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, Denmark, Finland, Georgia, Greece, Hungary, Republic of Moldova, Netherlands, Norway, Portugal, Romania, Serbia, Slovak Republic, Sweden and Switzerland) have eight Vice-Presidents between them, with half changing each year; the other 17 delegations have four Vice-Presidents between them, with two changing each year. Where there is rotation, it is by the English alphabetical order.
The function of a Vice-President is to take the Chair in the Assembly on any occasion when the President is unavailable. While doing so, the Vice-President exercises the powers, and is subject to the obligations, laid upon the President under Part V of the Rules of Procedure. Thus, as with the President, a Vice-President may not both take the Chair during a debate and otherwise take part in that debate. When a Vice-President is in the Chair, his or her Substitute may take the Vice-President's place in the Assembly, and may speak and vote there. The Official Report of debates refers to a Vice-President when he or she presides as "the President". Unlike the President, Vice-Presidents do regularly speak in debates which they have not chaired.
While Vice-Presidents hold the same powers of President when presiding, it is customary for the President to chair the most important parts of proceedings, in particular proceedings when distinguished visitors address the Assembly. The President will also act as the normal spokesperson and representative of the Assembly.
Vice-Presidents are also automatically members of the Bureau.