Ohio recognizes five parties besides the Democratic and Republican Parties. The only minor party member who filed in any primary for U.S. Senate is Joseph R. DeMare, who submitted 622 signatures to be listed on the Ohio Green Party primary. He will be the Green Party nominee if his petition has at least 500 valid signatures. The petition will be checked by mid-January 2012. The current U.S. Senator for that seat is Sherrod Brown, a Democrat.

Although the primary filing deadline for U.S. Senate has passed, the filing period for presidential primary candidates still has not passed. That deadline is December 30. It is somewhat likely that the Greens will be the only minor party with any nominees listed on their presidential primary ballot as well. Jill Stein and a delegation pledged to her are circulating a presidential primary petition. If the Stein petition succeeds, she will be the first person ever to run in a minor party presidential primary in Ohio.

The other qualified minor parties in Ohio are Americans Elect, Constitution, Libertarian, and Socialist. Primary petitions are difficult in Ohio, because no one can sign if that person voted in a Democratic or Republican primary in 2008, unless that voter had gone to the trouble of filling out a form changing affiliation during 2009.