US Anti-Doping Agency chief executive Travis T. Tygart on Monday hailed the new Horseracing Integrity and Safety Act as the start of a "new era" for the sport.
The legislation, signed into law on Sunday night by US President Donald Trump, sets a national standard for anti-doping rules and racetrack safety regulations addressing the safety of horses and jockeys, overseen by USADA.
"This passage signifies the beginning of a new era in the storied history of the horse racing industry," Tygart said in a statement.
"The landmark legislation will establish a uniform approach to better protect horses and jockeys and to bolster the strength and fairness of the sport."
Federal prosecutors indicted trainers and veterinarians in March for drugging horses to make them faster, and concerns by US lawmakers about horse safety have grown in recent years.
USADA will help design rules and a testing model "to ensure clean competition for equine athletes," Tygart said.
"USADA welcomes the opportunity to partner with horse racing stakeholders to develop uniform rules and to implement robust independent testing and enforcement that will contribute to the longevity and legacy of the sport."