Dana White: Nate Diaz is WRONG -- Steroids Not Rampant in UFC

UFC Prez Dana White has lashed out at fighter Nate Diaz, telling TMZ Sports Diaz is not only wrong when he says "all UFC fighters are on steroids," he's also hypocritical.

White tells us, "The UFC unquestionably has the best drug testing program in all of sports. All done by the United States Anti-Doping Association."

Dana is quick to add Nate's own teammates, Gilbert Melendez and Jake Shields, were both busted for PEDs ... point out, "If you are cheating, you get caught."