Cathy Milliken was born in Australia, where she completed her music degree in piano and oboe performance. She continued her oboe studies in Europe with Heinz Holliger in Germany and Maurice Bourgue in France. In 1980, she cofounded the renowned Ensemble Modern of Frankfurt. As a member of this ensemble she has worked with composers and conductors such as Peter Eötvös, György Ligeti, Brian Ferneyhough, Frank Zappa, György Kurtág and Karlheinz Stockhausen who produced her solo CD of Spiral.
She began composing seriously in 1990, and has since received commissions for solo and chamber works, a chamber opera, music-theater, installations, electronic and radio-art works, which have been performed in major European music festivals, concert halls and art venues. The Hessische Rundfunk in Frankfurt coproduced a CD of her piece Sifr.
Cathy also performs with other groups that commission new works or perform personal works. These groups include Ventures, which she created with Carol Robinson and HCD-Productions, which she founded in 1994 with Dietmar Wiesner and Hermann Kretzschmar. HCD has produced a CD of music by Paul Bowles, and another of chamber music by Howard Skempton (on Mode), and in 1999 co-authored a radio piece which won the coveted “Prix Italia”.