Held annually in Las Vegas and, since 2005, sponsored by Caesars Entertainment Corporation (known as Harrah's Entertainment until 2010).
It dates its origins to 1970, when Benny Binion invited seven of the best-known poker players to the Horseshoe Casino for a single tournament, with a set start and stop time, and a winner determined by a secret ballot of the seven players.
The winner of each event receives a World Series of Poker bracelet and a monetary prize based on the number of entrants and buy-in amounts.
Over the years, the tournament has grown in both the number of events and in the number of participants.
Each year, the WSOP culminates with the $10,000 no-limit hold'em "Main Event," which, since 2004, has attracted entrants numbering in the thousands.
The victor receives a multi-million dollar cash prize and a bracelet, which has become the most coveted award a poker player can win.
As of 2017, the WSOP consists of 74 events, with most major poker variants featured. Other events played in the past include Chinese poker, Five card stud, and many others.
However, in recent years, over half of the events have been variants of Texas hold 'em. Like most tournaments, the sponsoring casino takes an entry fee (a percentage between 6% and 10%, depending on the buy-in) and distributes the rest, hence the prize money increasing with more players.
Events traditionally take place during one day or over several consecutive days during the series in June and July. In the 2005 Main Event, US$52,818,610 in prize money was distributed among 560 players, with US$7.5 million as the first prize.
However, starting in 2008, the Main Event final table was delayed until November. The 2006 Main Event, won by Jamie Gold, is the largest single poker tournament by prize pool or by entrant numbers in history; Gold pocketed US$12 million for his victory.
The 20 Main Event final tables commenced in October because of the United States presidential election. In July 2010, it was announced that the winner of the 2010 Main Event would receive just under US$9 million.
As of May 2017, the World Series of Poker has done away with the November Nine concept and will instead crown the Main Event winner in July. On June 2, 2011, the World Series of Poker and Cirque du Soleil founder Guy Laliberté announced plans for an officially sanctioned special fundraising event, known as The Big One for One Drop, starting on July 1, 2012 with a record US$1 million entry fee.