"I'm looking forward to hitting the campaign trail with Marco to talk about the future of our country and the importance of electing a next-generation conservative in 2016."
Politico first reported the impending endorsement.
Chaffetz will hit the trail with Rubio on Friday as he holds a town hall event in Manchester, N.H., Rubio sits in second in the state, far behind Donald Trump and slightly ahead of fellow Sen. Ted Cruz (Texas), according to the RealClearPolitics average of recent polling.
The Utah lawmaker, who is Mormon, could also serve as an important ambassador to the Mormon community in Nevada, another early-nominating state.
Chaffetz is just the latest well-known Republican lawmaker to back Rubio.
Last week, House Benghazi Committee Chairman Trey Gowdy (R-S.C.) campaigned with Rubio, who on Wednesday was joined in New Hampshire by former Oversight Committee Chairman Darrell Issa (R-Calif.).