The most important event in professional snooker is the World Championship, held annually since 1927 (except during the Second World War and between 1958 and 1963). The tournament has been held at the Crucible Theatre in Sheffield (England) since 1977, and was sponsored by Embassy from 1976 to 2005. Due to the fact that tobacco companies are no longer allowed to sponsor sporting events in the United Kingdom after 2005, the World Snooker Championship had to find a new sponsor. It was announced in January 2006 that the 2006-2010 world championships would be sponsored by online casino 888.com.

Discussion has occurred about the whereabouts of future World Championships, focusing on the possibility of moving the tournament to another city (either in the UK or overseas), or to a bigger venue to accommodate the high spectator demand. This was concluded in 2005 with confirmation that the event will stay in Sheffield for at least a further five years. However, there are plans still to replace the Crucible in Sheffield, by building a new, high-capacity billiards arena.

The group of tournaments that come next in importance are the ranking tournaments. Players in these tournaments score world ranking points. A high ranking ensures qualification for next year's tournaments, invitations to invitational tournaments and an advantageous draw in tournaments.

Third in line are the invitational tournaments, to which most of the highest ranked players are invited. The most important tournament in this category is The Masters, which to most players is the second or third most sought-after prize.

To make snooker into a faster sport, in-line with Twenty-20 cricket, organised by Matchroom Sport Chairman Barry Hearn in conjunction with Sky, the shot-timed BetFred Premier League was established, with the top eight players in the world invited to compete at regular United Kingdom venues, televised on Sky Sports, and syndicated worldwide. Ronnie O'Sullivan is the current champion. Players have twenty-five seconds to take each shot, with a small number of time-outs per player.

There are also other additional snooker championships that have less importance, which don't give any world ranking points and aren't televised. These can change on a year-to-year basis depending on calendars and sponsors. The World Snooker website has full details.