Roemer said he would be continue to seek the presidency through the Reform Party and is entering Americans Elect, a non-partisan, non-profit group holding a national online primary.
In a statement posted on his campaign Web site, the 68-year-old former Louisiana governor and congressman said he would officially end his bid for the Republican nomination Thursday and expressed frustration at being excluded from the GOP presidential debates.
"As the GOP and the networks host debate No. 20-something this evening, they have once again turned their backs on the democratic process by choosing to exclude a former governor and congressman," Roemer said.
"I have decided to take my campaign directly to the American people by declaring my candidacy for Americans Elect. Also, after many discussions with The Reform Party, I am excited to announce my intentions of seeking their nomination.'
Roemer, whose candidacy has failed to get him into double-digit support in the polls, has positioned himself as an outsider who could unite Americans.
"It is time to heal our nation and build a coalition of Americans who are fed up with the status quo and the partisan gridlock that infects Washington," he said. "Together, we will take on the special-interests that control our leaders and end the corruptive influence of money in politics so we can focus on America's top priority-- jobs."
Roemer was Louisiana's governor from 1988 to 1992 after having served in the U.S. House from 1981 to 1988.
He defected from the Democratic Party to the Republicans in 1991. He was then defeated in his bid for re-election that year and lost again in 1995.