Each country may send a maximum of four athletes who have attained the A qualification mark in each specific event.
Area Champions (i.e. athletes who have won an event at their continental level championships) are granted automatic entrance, irrespective of whether they have achieved the qualification marks.
Furthermore, host countries may enter one unqualified athlete if no one of the respective nationality has achieved the required mark.
If there are not sufficient qualified entries in each event, the IAAF will invite the next highest ranked athletes to fill out the field, except in races 5,000 metres and longer.
If a country does not have a qualified athlete in any events, one representative will be allowed to compete in a preliminary round of the 100 metres.