After the audience voted, the singing contest said goodbye Thursday to Alex Lambert of North Richland Hills, Texas; Todrick Hall of Arlington, Texas; Lilly Scott of Littleton, Colo. and Katelyn Epperly of West Des Moines, Iowa.
It was no surprise that the judge's favorite from previous weeks, Michael "Big Mike" Lynche, made the cut.
Lynche dazzled the judges with his performance of "This Woman's Work" and made judge Kara DioGuardi dissolve into tears.
Lambert, who had trouble overcoming his shyness on stage, looked downcast when he learned his fate.
"There's a lot of things America hasn't seen me do yet," he said, adding, "I wish could just have broken out of my shell."
Judge Ellen DeGeneres gave him a verbal pat on the back.
"You're so good. Don't ever stop believing in yourself," she told him.
Perhaps the biggest surprise of the evening was the audience's rejection of Scott. Before the decision was announced, host Ryan Seacrest stood with Scott and Katie Stevens on stage and asked the judges to weigh in on the fact that one of them would be heading home.
DioGuardi, who had championed both singers, said she found it striking that it came down to these two. She said Scott was someone who understood herself as an artist and Stevens was struggling to do that, but had the advantage of being more contemporary.
"I thought I did really well. I put my heart into every performance," Scott said. "I just know there's an audience out there for me."
Judge Randy Jackson liked Hall's performance of "Somebody to Love," while Cowell said it was a mixed performance.
"This has been an awesome experience. I came here to prove that I'm not just a dancer, I can also sing. I think that I've done that," said the 24-year-old Hall.
He got some encouragement from Jackson, who said, "Fantastic, dude."
DioGuardi criticized Epperly for "going through the motions" on her version of "I Feel the Earth Move" this week. Cowell compared her performance to request night at a restaurant, but added that he did like her full, curly locks that evoked the song's composer, Carole King.
"I'm not stopping now. It's just a push actually, for me. I'll do more stuff," Epperly said.