Using the Internet to engage in illegal gambling is a violation of federal law. The Unlawful Internet Gambling Enforcement Act (UIGEA) prohibits transfers of money to online gambling sites. In addition, federal law prohibits payment providers from accepting financial instruments from illegal Internet bets.

Online gambling is primarily a matter of state law, but federal law also reinforces state law in cases. In 2000, six hundred to seven hundred gambling sites were operating. In 2005, sports book betting accounted for one-third of all Internet gambling.

Internet gambling is a growing industry, but questions remain about its legality. Some argue that the Constitution guarantees free speech, while others argue that the Commerce Clause gives the federal government the right to regulate gambling. Neither of these claims has been able to garner much support.

The most common types of online gambling are casinos, sports betting, and virtual poker. Some sites offer free play to practice, while others require users to register and submit personal information before they can gamble. Some sites accept debit and credit cards, while others accept electronic checks or wire transfers. In addition, some sites offer prizes for repeat business.

In 2005, online poker accounted for 18 percent of all Internet gambling revenue. The same year, online gambling revenues totaled more than $2 billion. This included revenues from sports books, pari-mutuel race betting, and lottery tickets.

Gambling on the Internet has a lot to offer, but it also carries the risk of criminal activity. In addition, it carries the risk of children and vulnerable people using the Internet to gamble.