Lightweights Joe Lauzon and Jim Miller were subject to out-of-competition drug tests prior to their fight at UFC 155 later this month.
MMAjunkie.com has reported that both fighters passed the tests for steroids and diuretics.
Nevada Athletic Commission executive director Keith Kizer confirmed the news. The commission had also tested Shane Carwin and Roy Nelson ahead of their planned meeting.
Miller is replacing Gray Maynard in the fight after Maynard suffered a knee injury in training.