It was previously reported Gingrich would leave the race Tuesday but a source described as close to the candidate told CNN it will happen Wednesday in Washington due to logistics.
Gingrich's spokesman said the former Georgia lawmaker will likely express his support for expected GOP nominee Mitt Romney, CNN said.
Republican voters not sold on Romney's conservative convictions kept Gingrich in the race even after he was left for politically dead last year when his campaign advisers quit. His campaign languished after the disagreement, but strong performances in the GOP debates gave him a boost, CNN said.
In December, Gingrich had a double-digit lead over Romney in the polls, but his Southern strategy failed with losses in Alabama, Mississippi, Tennessee and Louisiana.
Once Gingrich announces the end of his campaign, Romney and Rep. Ron Paul, R-Texas, will be the only candidates left in the bid for the GOP nomination.
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