Bartiromo will anchor a daily program for that network, plus a weekly business-oriented show for Fox News Channel.
The network says she begins at Fox Business on Feb. 1, with both programs set to launch by April.
Bartiromo left CNBC in November after 20 years. While there, she pioneered daily live reporting from the floor of the New York Stock Exchange. She has won two News and Documentary Emmys.
Her high-profile work and photogenic looks earned her the nickname "Money Honey."
At her new workplace, she reunites with Roger Ailes, Fox News chairman and CEO. He previously ran CNBC.
Ailes said he is "delighted to have her join me once again."