The E! reality star, 30, is not revealing the father's identity or how far along she is, E! News reports.
Speaking with E! Tuesday, she refused to say if she and ex-boyfriend Scott Disick were back together.
"You're going to have to see on the show," she said, referring to her new reality show with her sister Khloe, "Kourtney and Khloe Take Miami," which debuts Sunday.
In April, Kourtney's stepdad, Bruce Jenner, hinted a baby could be on the way.
"Kourtney is turning the big 3-0 this year and I'm wondering how she's going to handle that," he told Usmagazine.com at the 44th annual Academy of Country Music Awards.
Added Bruce, "Women have a lot more issues to deal with [than men]. They have ticking maternal time clocks to deal with and they have all these different sorts of things going on in their heads. The good news about all three girls [Kourtney's two famous sisters are Kim and Khloe] is that they're very busy. They work very hard and take their business very seriously. And a lot of times they don't even have time to worry about stuff like settling down."
"It's not like they're all just sitting around waiting for a man to show up and sweep them off their feet," he added. "They're ambitious, hard-working and driven. Sometimes it's tough to find a relationship when you're doing all that stuff."