Rumor has it that Tito Ortiz will be making 1 million dollars for fighting Ken Shamrock on SpikeTV this tuesday. This would be him rarified company indeed; people who have made over 1 million in a single MMA fight. The only other people I can think of who have commanded this is much is Royce Gracie and Rickson Gracie (who's rumored 2 million for fighting Funaki is the largest purse ever). There may be other million dollar paydays out there (and certain fighters have made over 1 million in a year thanks to endorsements and the like). Not bad for a sport relatively new in the United States, I hope to see those numbers higher of course:

Peanuts compared to boxing however, I'm trying to find records of the largest boxing purses. The first million dollar payday for boxing I believe was the Rumble in the Jungle between Ali and Foreman.