The state announced UltimatePoker.com is live, featuring nightly games with prizes of $1,000 and a higher-stakes game with a $10,000 pool on Sundays.
"This is, for Nevada, a new day," Reno gaming analyst Ken Adams told USA Today.
Nevada fast-tracked legislation in February authorizing online poker, and Ultimate Poker received final approval from gaming regulators this month for a 30-day field trial starting Tuesday.
Players must be at least 21 years old and physically within the state's boundaries to play, with UltimatePoker officials say will be policed by the company's "complicated and sophisticated" software.
New Jersey and Delaware, which have legalized online gambling to increase tax revenues, are expected to follow Nevada in the online poker arena soon.