During a sneak peek of Sunday's "Keeping Up with the Kardashians," Khloe told her sister Kim, "I don't know this person anymore. Bruce is gone, and I don't know Caitlyn. Simple as that."
In a previous interview, Khloe said that she referred to Caitlyn as "Bruce" and that she was okay with that.
"I don't mind talking to her — but it's not a real relationship anymore," she said.
Of Caitlyn's high-profile transition, Khloe said that the family had a tough time with it being so public.
"I think what people don't seem to remember is that, this is our real lives and that a lot of these things we are experiencing in real time," Khloe told an Australian radio show in July. "But I think there was a hard time for the entire family, that we were all transitioning with her, but in front of an audience, I think that's not really the normal way to go about it, you know."