The men's 100 metres was the shortest of the men's track races in the Athletics at the 1964 Summer Olympics program in Tokyo, Japan. It was held at the Olympic Stadium on 14 and 15 October 1964. 76 athletes from 49 nations entered, with 3 not starting in the first round. Nations were limited to three athletes each, per rules in force since the 1930 Olympic Congress. The first two rounds were held on 14 October, with the semifinals and the final on the following day. In the final, American Bob Hayes tied the world record of 10.0 seconds and won the gold medal. Enrique Figuerola of Cuba and Harry Jerome of Canada tied the old Olympic record time. It was Cuba's first medal in the event; Canada earned its first men's 100 metres medal since 1928. Background This was the fifteenth time the event was held, having appeared at every Olympics since the first in 1896. Neither of the top two runners from 1960 returned, but Rome bronze medalist Brit Peter Radford and fourth-place finisher Cuban Enrique Figuerola did. Other notable entrants were American Bob Hayes (the favorite who was unbeaten in the event, including the 100 yards variant, since 1962) and Canadian Harry Jerome (a 1960 semifinalist who held a share of the world record). A muscle strain prevented Venezuelan Horacio Esteves (another 1960 semifinalist with a share of the world record) from competing. Cameroon, the Republic of the Congo, the Dominican Republic, Iran, the Ivory Coast, Madagascar, Mali, Northern Rhodesia, Rhodesia, Senegal, and Vietnam were represented in the event for the first time. The new federation of Malaysia also competed for the first time, though both Malaya and Singapore had previously appeared. The United States was the only nation to have appeared at each of the first fifteen Olympic men's 100 metres events. Competition format The event retained the same basic four round format from 1920–1960: heats, quarterfinals, semifinals, and a final. However, after an extremely static format from 1936 to 1956, the format was modified for a second time in 1964 after 1960's tweaks. The changes generally increased the number of athletes in each race; for the first time in Olympic men's 100 metres history, 8 runners competed at a time. Records Prior to the competition, the existing World and Olympic records were as follows. Bob Hayes had an official time of 10.0 seconds in the