Both US lotteries are offering jackpots of more than $ 300m (£231m) for the first time.
In the seven years since all US lotteries started selling both Powerball and Mega Millions tickets, both games have never offered such large prizes at the same time.
Tuesday’s Mega Millions jackpot is an estimated $ 350m (£269m), while the windfall for anyone lucky enough to win the top prize in Wednesday night’s Powerball draw is $ 307m (£236m).
Those prizes are based on annuity options, where the cash is spread out in annual payments for 29 years.
Cash prizes would be an estimated $ 218.3m (£168m) for Mega Millions and $ 193.2m (£148.7m) for the Powerball.
However, even with the tempting prospect of even greater payouts, the odds of winning a jackpot remain a decided long shot.
Mega Millions players have a one in 258.9 million chance of matching all the numbers they need for a nine-figure windfall, and a Powerball win is even more unlikely at one in 292.2 million.