Trump and other pageant leaders said Prejean was being sacked not because of her controversial remarks but because she hadn't been holding up her end of the agreement she signed when she entered the pageant.
"This was a decision based solely on contract violations, including Ms. Prejean's unwillingness to make appearances on behalf of the Miss California USA organization," the California pageant's executive director, Keith Lewis, said in a statement.
Lewis had complained at a news conference last month that Prejean was skipping Miss California USA events while speaking out against gay marriage at unsanctioned appearances.
After the complaints reached Trump, who owns Miss California USA's parent organization, the mogul decided to give her a second chance and keep her on. On Wednesday he changed his mind and sided with Lewis.
"I told Carrie she needed to get back to work and honor her contract with the Miss California USA Organization and I gave her the opportunity to do so," Trump said in a statement. "Unfortunately it just doesn't look like it is going to happen."
Prejean spokeswoman Melany Ethridge declined to comment, saying she hadn't been able to reach the former beauty queen since the announcement of her ouster.
Prejean told the television show Access Hollywood she would never have been let go from the pageant had she not replied the way she did to a judge's question about gay marriage.
"It's just because of my answer, I think," Prejean said Wednesday shortly after learning of Trump's decision. "None of this would be happening right now if I just said, 'Yeah, gays should get married.'"
She also denied being derelict in her post-pageant duties.
"I've tried to reach out to them and I've done several appearances and I'm going to be presenting at the Special Olympics this weekend as an honorary guest," Prejean told the TV show. "I mean, I've been cooperating with them. I don't see why this is happening."
Pageant officials said Prejean would be replaced by the Miss California pageant's first runner-up, Miss Malibu Tami Farrell. They had announced last month that Farrell was being named a special ambassador to fill in for Prejean at any events she didn't attend.
"Carrie is a beautiful young woman and I wish her well as she pursues her other interests," Trump said.
Prejean, 22, was competing in the Miss USA competition, where she was first runner-up, when she answered gossip blogger Perez Hilton's question about gay marriage by saying wedding vows should be reserved for men and women.
"No offense to anybody out there, but that's how I was raised," she said.
After the response made her a lightning rod for the gay-rights debate she began speaking to crowds opposed to gay marriage, violating a section of her contract that required she clear unsanctioned appearances with pageant officials. About the same time, seminude photos of her began to surface on the Internet.
Although the photos were mild, pageant officials said she also violated her contract by not disclosing their existence to them.
When Trump initially decided to keep Prejean on, Lewis' co-executive director, former Miss USA Shanna Moakler resigned in protest.
"My faith has been restored in the Miss Universe Organization and with Donald Trump," Moakler said in a statement after Wednesday's announcement. She didn't say whether she planned to return to the organization.
Copyright 2009 The Associated Press.