Carol Jantsch, a senior at the University of Michigan, will replace Paul Krzywicki, who retired at the end of the 2004-05 season.
Orchestra officials believe that she will be the first woman ever to play the tuba in a major American orchestra. She will also be the youngest member of the Philadelphia Orchestra.
"The appointment of this young woman will mean the rejuvenation of the Orchestra in the best way," said Christoph Eschenbach, the orchestra's music director. "The fact that she is a young woman playing a very un-woman-like instrument is really extraordinary, and it is almost a miracle that she is both so young and so accomplished."
Jantsch has played with the Detroit Symphony and the Columbus Symphony. In 2004, she won the Leonard Falcone International Euphonium and Tuba Competition, the International Tuba-Euphonium Association's Artist Solo Tuba Competition, and the International Instrumental Competition Markneukirchen in Germany.