During the interview, Fiorina chatted about her opponent Donald Trump and Russia's President Vladimir Putin, who she recently met in Beijing.
Of Putin, she shared, "I would describe him as a formidable adversary. He's very confident. He actually can be quite funny and charming. But he's a KGB guy. We should never forget this."
Fiorina also likened Trump to Putin, saying, "The two of them have a lot in common, actually. But we'll just leave it at that."
When asked about her thoughts on the two men possibly meeting, she said, "I wouldn't talk to him at all. I think Donald Trump is wrong. I think we've talked way too much to Vladimir Putin."
Fiorina also criticized Republican candidate Ben Carson, who made comments about not wanting Muslims in the White House. She told Fallon, "Well, I think that's wrong. You know, it says in our Constitution that religion cannot be a test for office. It is also true that this country was founded on the principle that we judge each individual and that anyone of any faith is welcome here.