The bout takes place Saturday at the MGM Grand Hotel in Las Vegas, Nev.
De La Hoya, 34, is a six-weight world champion and Mayweather, 30, the champion, is undefeated in 37 professional fights with 24 knockouts.
He is considered the faster and sharper boxer by most analysts, but is moving up to 154 pounds, the heaviest weight in his career.
Some analysts predict that will be an advantage for the bigger and physically stronger De La Hoya.
"When you're facing Floyd Mayweather, you're facing the best, period," said an undaunted Mayweather. "I feel tremendous. I've said what I had to say, and now the physical part comes."
This bout will be carried in 176 countries and is expected to eclipse the standing revenue record of $70 million for non-heavyweights set in 1999 when De La Hoya fought Felix Trinidad.