The International Mathematical Olympiad (IMO) is the World Championship Mathematics Competition for High School students. This annual event began in 1959 in Romania, with 7 countries participating and has gradually expanded to over 80 countries from 5 continents. The location alternates each year, with the current 2004 IMO scheduled for July 4-18 in Athens, Greece. The IMO Advisory Board ensures that the competition takes place and that each host country observes the regulations and traditions. The official delegation to an IMO consists of a maximum of six students and two leaders. There is no official team and different countries have different methods of training and selecting students for an IMO. More information on the selection of problem questions, the competition process, the marking of the papers, and other procedures are provided on this website. Also posted online are competition results and exam problems from previous Olympiads, related materials, countries with Olympiad sites and a listing of previous competitions by year.