"My six-second mistake is well known, but Claire McCaskill's six-year record is something you should know," says Akin in the ad, directly to viewers.
Akin takes on McCaskill's support of President Obama'a signature healthcare legislation, and accuses the sitting senator of not paying taxes in the 30-second spot.
The ad, which will air across Missouri, echoes previous attacks from the Akin campaign, blasting his political rival for not paying taxes on her private plane and supporting the Affordable Healthcare Act.
Last year McCaskill was repeatedly hammered for unpaid back taxes on a private plane, including ads produced by Karl Rove's Crossroads super-PAC. She has since repaid the taxes and sold the plane.
Akin was admonished this month by political opponents, as well as fellow Republicans, for suggesting that woman would not get pregnant from a “legitimate rape" during a local television interview.
The National Republican Senatorial Committee and super-PAC backers have pulled funding from the GOP Senate hopeful, and numerous Republicans have called on Akin to get out of the race, including Sen. Roy Blunt (R-Mo.).
"He's an engineer, he's a quantitative guy. I think at some point you have to add up the columns here and my belief is that by anyway you add them up, they don't add up," said Blunt on MSNBC's "Daily Rundown" Wednesday morning.
However, Akin has maintained that he will stay in the race, defying Congressional leaders and his party's GOP presidential ticket. His campaign raised more than $200,000 in contributions online as of last week, according to CNN, due to a fundraising push that called on supporters to help beat McCaskill and "fight back against the party bosses."
Akin and McCaskill were in a tight race for Missouri's senate seat, but polls taken after his comments show that voters may have shifted in the Democrats' favor.