"I like the exchanges," Enzi is quoted as saying in the ad. "These exchanges can be good."
"Good?" a voiceover in the ad responded. "Wyoming's Obamacare exchange has the most expensive premiums in the country, and it's marred by glitches."
The ad ends with the tagline "tell Mike Enzi we don't like these liberal, Big Government Obamacare exchanges."
Enzi, one of the most conservative members of the Senate, voted against the Affordable Care Act back in 2010. He also supports efforts to repeal the law.
Enzi is currently facing a primary challenge from Republican Liz Cheney, the daughter of former Vice President Dick Cheney.
Watch the ad below: