89 Super League players tested negative for banned substances following an intesive drugs testing programme in November.
The RFL said that the UK Anti-Doping agency conducted 119 tests on players from 11 different clubs over a three-day period. Testers made impromptu visits to the players at their clubs and homes.
Nigel Wood, RFL chief executive expressed his pride at the results.
“Whilst I am not surprised by the results, it is nevertheless a matter of some pride for the players and the sport that all 119 tests came back negative,” he said.
“In terms of participation levels, no other sport is more vigilant when it comes to doping than Rugby League and we will continue to work closely with both UKAD and our players and clubs to ensure we remain as clean and safe as possible.
“As pleased as we are, there will be no relaxation of vigilance following this terrific set of results, for which I hope the players and the sport are given due credit.”
The testing was only the second time the UK Anti-Doping agency had performed such an intensive programme.
All of the players tested were 100 per cent clean with no traces of any performance enhancing drugs found.