The original World Series of Poker was started by Tom Morehead of the Riverside casino in Reno and was an invitational event. The set of tournaments the World Series of Poker (WSOP) would evolve to was the brainchild of Las Vegas legend, casino owner, and poker player Benny Binion as well as his two sons Jack and Ted.

The Binion family not only nurtured the WSOP, but poker in general. Prior to the 1970s, poker was not found at many casinos because of the difficulty of keeping cheaters out. Through better security techniques as well as the Binion's tireless promotion through events like the WSOP, poker became a very popular game.

In 1970 the first WSOP at Binion's Horseshoe took place with seven players. The winner, Johnny Moss was elected by his peers as the first World Champion of Poker and received a silver cup as a prize.

From 1971 on, all WSOP events have been tournaments with cash prizes. In 1973 a new event, five-card stud, was added to the main event of no limit Texas Hold 'em. Since then new events have been added and removed. In 2006 there will be 42 events at the WSOP, covering the majority of poker variants. Event winners get, in addition to their prize money, a coveted gold bracelet.

Doyle "Texas Dolly" Brunson and Johnny "Oriental Express" Chan have each won ten bracelets, while Phil Hellmuth has nine. Doyle's son, Todd Brunson, won a bracelet in a pot limit Omaha event in 2005, making them the first father/son combo to win at least one event at the WSOP. Also, celebrities Patrick Bruel and Jennifer Tilly have won WSOP bracelets in 1998 and 2005 respectively.

The number of participants in the WSOP has grown every year, and in recent years the growth has exploded. In 2000 there were 4,780 entrants in the various events, but in 2005, the number rose to over 23,000 players. In the main event alone, participants grew from 839 in 2003, to 2,576 in 2004, to 5,619 in 2005. For the 2006 main event, a cap of 8,000 players has been established. Much of this growth can be attributed to the WSOP airing on ESPN and the World Poker Tour being shown on the Travel Channel, along with other televised series, as well as the boom of online poker.

Like most tournaments, the sponsoring casino takes a "rake" (a percentage between 6%-10%, depending on the buy-in) and distributes the rest, hence the prize money increases with more players. In the 2005 main event $52,818,610 (US) in prize money was distributed, including a $7.5 million first prize. Subtracting the $10,000 buy-ins, over $47 million was won by 560 players in the event.

In 2004, Harrah's Entertainment purchased Binion's Horseshoe, renaming it just "Binion's" and announced that the 2005 Series events would be held at the Harrah's-owned Rio Hotel and Casino, located just off the Las Vegas Strip, with the final two days of the main event held downtown at Binion's in celebration of the centennial of the founding of Las Vegas. It also added a made-for-television $2 million "freeroll" invitational "Tournament of Champions" (TOC) event won by Annie Duke as a "winner-take-all" event.

Starting in 2005, the WSOP began a tournament "circuit" at Harrah's-owned properties in the United States where in addition to the $10,000 buy-in tournament at each site, qualifying players became eligible for a revamped Tournament of Champions. The 2005 TOC, made up of the top twenty qualifying players at each circuit event, along with the final table from the 2005 Main Event and the winners of nine or more bracelets (Hellmuth, Chan and Doyle Brunson) would participate in the revamped TOC at Caesar's Palace. Mike "The Mouth" Matusow won the first prize of $1 million (US), and all the players at the final table were guaranteed a minimum of $25,000 for the eighth and ninth place finishers. During a break in the final table of the 2005 Main Event on July 16, Harrah's announced that eleven properties ? including the recently added Bally's and Caesar's properites ? would host 2005-06 WSOP Circuit events that started on August 11 in Tunica, Mississippi. (One event, that was scheduled for Biloxi, Mississippi was cancelled after the Grand Casino Biloxi, which was scheduled to host the event, suffered major damage from Hurricane Katrina. A second event, scheduled to be held at Harrah's New Orleans, Louisiana property, is in limbo due to damage that it also suffered in said hurricane.)

The Rio will again host all 2006 WSOP major events, begining on June 25 with satellite events and formally start the next day with the annual Casino Employee tournament, and will feature the TOC on June 28 and 29, 2006, along with the various events leading up to the main event, which will be held from July 28 until August 10. If the limit of 8,000 players buying in for $10,000 each is reached, the first prize is estimated to be $10 million as well as a special bracelet different than the others.

Like any event or sports league, the WSOP also has corporate sponsors and licensed products, which like any leagues or events, pay fees to market themselves as an official sponsor and/or licensee and exclusively use the WSOP insigina and cross-promote with their events. Besides the Harrah's properties and ESPN, major sponsors have included Miller Brewing's "Milwaukee's Best" brand of beers, Pepsi's SoBe Adreneline Rush energy drink (sponsors of the 2005 TOC), Helene Curtis' Degree brand of anti-perspirant/deodorant, Card Player magazine, and GlaxoSmithKline/Bayer's Levitra erectile dysfunction medicine are all official corporate sponsors. Licensees include Activision (video games for different plaforms such as Nintendo's GameCube, Microsoft's Xbox, Sony's PlayStation 2 and PC featuring computer generated versions of stars like Ferguson among others), and products made by different companies ranging from chip sets, playing cards, hand held games and clothing like caps and shirts. The fees and licences bring in over a million dollars to Harrah's.

The main event of the WSOP is the $10,000 buy-in no-limit Texas Hold 'Em tournament since 1972. (In 1971, the buy-in was $5,000.) Winners of the event not only get the largest prize of the tournament and a gold bracelet, but additionally their picture is placed into the Gallery of Champions at Binion's.

There have been many memorable events during the main events, including Jack Straus's 1982 comeback win after discovering he had one $500 chip left when he thought he was out of the tournament.

Four players have won the main event multiple times: Johnny Moss (1970, 1971 and 1974), Doyle Brunson (1976 and 1977), Stu Ungar (1980, 1981 and 1997) and Johnny Chan (1987 and 1988.)

The end of the 1988 main event was featured in the movie Rounders.

Chris Moneymaker and Greg Raymer, the winners in 2003 and 2004 both qualified for the main event through satellite tournaments at the PokerStars online cardroom.

Several living poker legends have tried unsuccessfully for years to win the main event, including T. J. Cloutier, the 1985 and 2000 runner-up.