Nagano told members of the opera's board of directors that he would leave when his three-year contract expires on June 30, 2006.
The announcement came as little surprise. Earlier this year, Nagano was chosen to succeed Zubin Mehta as music director of the Bavarian Opera. And in March, he was tapped for the same role at Canada's Montreal Symphony. According to a statement from the opera, Nagano discussed his plans with Plšcido Domingo, the company's general manager, and artistic director Edgar Baitzel shortly after accepting the post at the Montreal Symphony.
"I want to state publicly what I've said to him in person, that all of us at the Company are deeply appreciative of his wonderful achievements here and that we fully understand his acceptance of the two new posts," Domingo said in a statement.
Nagano will also step down from his position as chief conductor and artistic director of the Deutsches Symphonie-Orchester Berlin, a post he began in 2000. He will continue to work with that orchestra on a project basis through 2008, according to the company's web site.
Nagano continues his close relationship with the Berkeley Symphony, where he has served as musical director since 1978.
A California native, Nagano was formerly principal conductor for the Los Angeles Opera. He became the company's first music director in 2001. Nagano said in a statement that he hopes to return to the Los Angeles Opera as a guest conductor, and that he looks forward to the next two seasons with the company.