Manchester United, last season's runner-up, is top-seeded with Benfica, Switzerland's FC Basel and Romanian newcomer Otelul Galati.
Bayern Munich, whose stadium will stage the final next May, got a tough group with Villarreal, big spenders Manchester City and Napoli.
Real Madrid, the nine-time European champion, faces Lyon, four-time winner Ajax and Dinamo Zagreb.
Inter Milan, the 2010 winner, is top-seeded in a group with CSKA Moscow, Lille and Turkey's Trabzonspor.
Each team plays six matches in a program scheduled from Sept. 13 through Dec. 7.