Kentuckians for Strong Leadership (KSL) is spending "several thousands of dollars" on the ad, according to a release.
It highlights Grimes' support of ObamaCare — she's previously said that she'd like to make changes to the law, but doesn't support its full repeal — and characterizes that stance as "wrong."
It includes a clip of Obama declaring that those who like their healthcare plans can keep them, and labels that claim "wrong."
"Don't trust people who are wrong," text on the ad reads.
The release indicates the ad is meant as a direct response to attacks from the Democratic National Committee from earlier this week. The DNC launched robocalls, search and social ads blaming a handful of top Republicans — including McConnell — for the shutdown.
Polling has shown Republicans receiving the brunt of the blame for the government shutdown, and Democrats have been working to take advantage of the potential voter backlash against the GOP.
But Republicans believe the nation is so dissatisfied with Obama's health care law that their efforts to dismantle it will insulate them from backlash.
While KSL goes on offense for McConnell, his own campaign is up with a radio ad that parries hte DNC's attacks.
The ad, which will run for two days on radio and digital, features McConnell accusing Senate Majority Leader Harry Reid (D-Nev.) and President Obama of prolonging the shutdown by refusing to compromise.
“Angry with Washington? So am I," he says in the ad.
"We all agree: this government shutdown is a disgrace, and it’s hurting our country. Republicans continue to offer solutions to reach a compromise. And I’ve worked to pass a short-term bill to keep the government open while we talk. But, President Obama and Harry Reid have refused to negotiate."
McConnell adds: "It’s a shame, because we owe it to you to negotiate a solution and restore your faith in Washington."
He also says that until the shutdown ends, he's donating his paycheck to charity.