Buchanan, a conservative political commentator, made the prediction in an interview with "Exclusiva," an ABC News Hispanic news program, ahead of Tuesday's midterm elections and said he himself is somewhat disillusioned with the Republican Party.
"There's the spending orgy, the arrogance of power, for me," Buchanan said. "The war in Iraq, failure to protect our border, hurting the working class in Ohio, for example, the list goes on and on. We're more dissatisfied with the Republican Party than we've ever been."
Buchanan has served as an adviser to three U.S. presidents and unsuccessfully ran twice for the Republican presidential nomination.
Various polls indicated Democrats appear poised to retake a majority Tuesday in the House of Representatives they lost in 1994, although Senate dominance is much closer in the polls.