Former Massachusetts Governor Mitt Romney beat former Pennsylvania Senator Rick Santorum by only eight votes in Iowa, the first state to vote on who will be the Republican Party's presidential candidate.
Iowa GOP Chairman Matt Strawn announced Wednesday morning Romney had obtained 30,015 votes against Santorum's 30,007 to kick off the program of voting in state caucuses around the country.
The razor-thin margin separating the two means they are basically tied as Iowa only sends 28 delegates to the Republican national convention, which has some 2,000 delegates.
The two front-runners were almost tied at about 25 percent each and will now head for New Hampshire, where the next contest will be held in a week.
In speeches to supporters after the close result became increasingly clear, both candidates blasted President Barack Obama, with Santorum slamming him for "crushing business" with regulations, while Romney criticized his economic and foreign policies.
Both candidates looked ahead, with Santorum saying "we will be in New Hampshire and with your help and God's grace, we'll have another fun night a week from now."
Apart from the two front-runners, Ron Paul, the libertarian-leaning congressman from Texas, came in third with 21 percent of the vote followed by Newt Gingrich, the former House speaker, with 13 percent, and Rick Perry, the Texas governor, 10 percent. Perry announced he would return to his home state to "reassess" his campaign.
"With the voters' decision, I decided to return to Texas and determine if there is a path forward," Perry told supporters at a rally in Des Moines, capital of Iowa.
"With a little reflection ... I am going to decide the best path forward. There is a model to take this country forward and it is in the great state of Texas."
Michele Bachmann, the Minnesota congresswoman, was in a disappointing sixth place. Jon Huntsman, the former ambassador to China, came in seventh.