The Florida Republican said changes to the bill added in the Senate helped sway her.
"The sweetener for me was help for the middle-class families," she told the AP. "I considered Monday's bill to be a bailout for Wall Street. I don't see that this bill has that focus. It's relief for middle-class families."
Ros-Lehtinen said she called a relieved House Minority Whip Roy Blunt Thursday morning to tell him the news. Blunt has been in charge of rounding up GOP votes.
"He was glad to hear it," she said.