The celebrity billionaire's campaign team said Trump will be in Wichita, Kansas, for a rally tomorrow prior to the state's caucus that day.
"Because of this, he will not be able to speak at CPAC (Conservative Political Action Conference) as he has done for many consecutive years," it said in a statement Friday.
CPAC also confirmed the cancellation, while managing to knock the real estate tycoon's conservative bona fides.
"Very disappointed @realDonaldTrump has decided at the last minute to drop out of #CPAC," the organisation said on Twitter.
Trump's bombastic style and aggressive messaging has dominated the Republican nomination contest since he entered the race last June.
But with his surge to the fore, winning 10 of the first 15 statewide contests, establishment Republican Party figures and other conservatives have begun expressing deep concern about a Trump nomination and are seeking a way to derail his victory march.