Alec Baldwin has revealed the news in his recent interview to New York Magazine. He said, "I will tell you one thing. And that is our show next year is our last year of the show. Our contracts are expired [in 2012], and Tina is gonna have a big career directing films and writing. She's going to be the next Elaine May. She'll be great."
In 2010, the actor had told CNN that he was going to leave the show once his contract ends in 2012. Later, his rep had claimed that he had no such plans. Now, neither NBC nor Tina Fey has responded to his statement. But a NBC insider says, “We have had no conversations about '30 Rock' ending next season."