With the Ohio secretary of state's office reporting 8,278 of 9,421 precincts (87.87 percent) counted, Romney had 37.86 percent (409,551) of the votes to Santorum's 37.36 percent (402,421). Newt Gingrich was third with 14.55 percent (57,361) and Ron Paul was fourth with 9.24 percent (99,954). Rick Perry and Jon Huntsman, who have pulled out of the race, each polled less than 1 percent.
Polls leading up to the Super Tuesday primary had projected it would be too close to call in the key Republican battleground state between Romney, the former Massachusetts governor, and Santorum, the former U.S. senator from Pennsylvania.
There are 66 delegates at state in Ohio's winner-take-all primary.
2014: The Year in Music [PHOTOS]