Reigning European champions Bayern Munich have been grouped with Manchester City, Russian champions CSKA Moscow and Czech club Viktoria Plzen for the European Champions League.
Chelsea are grouped with Bundesliga club Schalke, 1986 European Cup winners Steaua Bucharest and FC Basel.
English champions Manchester United will be favourites to qualify for the last 16 from their group against Ukraine's Shakhtar Donetsk, Spanish outfit Real Sociedad and Bayer Leverkusen.
Arsenal came off the worst of all, the English contenders in a Group F that contains last season's runners-up Borussia Dortmund, Marseille and Napoli.
Group H is bustling with history, as Barcelona, AC Milan, Ajax and Celtic - with 16 European Cups between them - come together.
Elsewhere, Real Madrid face Juventus, Galatasaray and FC Copenhagen in Group B.
