Manchester United, last season's runner-up, is a top seed with Benfica, Switzerland's FC Basel and Romanian newcomer Otelul Galati.
Bayern Munich, whose stadium will stage the final next May, drew 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 seeded first in a group with CSKA Moscow, Lille and Turkey's Trabzonspor.
Each team plays six matches in a competition that runs from Sept. 13 through Dec. 7.