Participation in the IMO is by invitation only. Each invited country is entitled to send a team consisting of up to six contestants, a Leader and a Deputy Leader. Contestants have to be less than 20 years of age and not formally enrolled at a university or any other equivalent post-secondary institution. The country that hosts the IMO provides accommodation, meals, and land based transport for the team. The contestants write two papers, on consecutive days, each paper consisting of three questions with four and half hours to answer. Each question is worth seven points and a total score of 42 points is possible. Awards are determined roughly as follows:

GOLD MEDAL: the top 1/12 of scores receives gold medals.
SILVER MEDAL: the next 2/12 of scores receives silver medals.
BRONZE MEDAL: the next 3/12 of scores receives bronze medals.
HONORABLE MENTION: any contestant who receives a perfect score of 7 on any one questions, but who does not receive a medal, is awarded an honorable mention.