World championships were first held in 1893, in Chicago, under the ICA. They were for amateurs. Separate professional races were held from 1895, in Cologne. Amateurs and professionals competed in separate events until 1993, after which they raced together in "open" races. Championships are open to riders selected by their national cycling association. They compete in the colours of their country.
The winner of ICA championships received a gold medal. The UCI awards a gold medal and a rainbow jersey to the winner. Silver and bronze medals are awarded to the second and third place contestants. World champions wear their rainbow jersey until the following year's championship, but they may wear it only in the type of event in which they won it. Former champions can wear rainbow cuffs to their everyday jerseys.
World track championships are allocated to different countries each year. They are run by that country's national cycling association, although the top referees (President of the Commissaire's panel – PCP, Secretary, Starter, and Judge Referee) are International Commissaires appointed by the UCI.
Venues
To take advantage of the best weather conditions and reduce the risk of weather-related program changes, the UCI has long organized track world championships in the summer. Until 1966, the competition must by regulation take place on an open-air velodrome. It was not until the 1969 edition, organized at the Antwerps Sportpaleis, that the first championship was held on an indoor velodrome. From 1987, the trend reversed and indoor velodromes took over. From 1987 to 1995, there were five world championships organized on an indoor velodrome. Colombia hosts in 1995 the last track world championship organized outdoor.