The former The Hills star, 30, made the big announcement on Instagram Friday.
"I finally figured out what to get Corey for Christmas! #babyontheway #ClearblueConfirmed #ad (blog post with all the details will be up today, couldn't wait to share the news with you all:)! Xoxo," Patridge captioned a photo of herself holding a positive pregnancy test.
Patridge told Us Weekly she was "super excited" about the news and had to ask Bohan to confirm the test's results just to make sure she "wasn't seeing things."
"You never really expect it to say 'Pregnant.' He had a big smirk on his face and was really happy about it," Patridge said. "I feel at this point in my life I am ready to be a mama!"
Patridge and Bohan have had an on-again, off-again relationship with 2008. They split in 2009 but got back together a year later. Bohan just proposed in November at the Summit House restaurant in Orange County, CA, and Patridge admitted she definitely didn't see it coming.
"When dessert time came he ordered cheesecake and the waiter brought it out on a platter with a beautiful silver cover. I noticed all the waitresses gathering with phones and thought, 'What is going on!?' Then all of a sudden the waiter lifted the silver cover and I saw the ring in a box with white rose petals on the plate," the reality TV star recently told People.