The Democrat ran unopposed in her party, but that didn't stop her from making several campaign stops around the state to speak out about her campaign.
She started the day by casting her vote in Kirkwood near St. Louis, telling reporters it was like Christmas morning in a way, saying she finally gets to unwrap the present and see who her opponent will be in November.
She also said she thinks the race between John Brunner, Sarah Steelman and Todd Akin is still too close to call. She said it depends on turnout and believed the race would favor Akin if we see low voter turnout statewide.
"We have candidates who are willing to privatize Medicare, Social Security, and take away student loans before they take one dime away from big oil. So I think those priorities are out of sync with most Missourians."
Sen. McCaskill traveled to Columbia for a campaign stop before making her way to Kansas City to watch returns at her Clay County headquarters.
"I think people are really frustrated with Washington right now," she said. "I get that. I am too. But we have been stuck because so many people who came to Washington recently just want to shut it all down."
She went on to call herself a Missouri moderate and told supporters she's not afraid to stand up to Harry Reid or President Obama. She told campaign volunteers that more than $15 million has already been spent in Missouri by outside groups during the primary to oust her from office.
McCaskill says tomorrow will be the start of the real campaign season for her, although she has been running ads recently against some of her Republican challengers.
McCaskill plans to make her first official re-election campaign stop in Kansas City Wednesday morning at Standard Sheet Metal, saying she will start telling the state what she's done to protect and grow jobs over the last six years.