Tough draw for Saints
Northampton will open their next tilt at the Heineken Cup title in a challenging pool containing European heavyweights Munster.
Saints, beaten 33-22 by Leinster in a gripping final last month, will meet the two-times winners who dumped them out in the knockout stages in 2010.
Pool 1 also includes Welsh region the Scarlets and French club Castres.
The draw has been kind to Leinster with the champions grouped alongside Bath, Glasgow and tournament debutants Montpellier.
English clubs have endured mixed fortunes, but London Irish have been granted one of the easier routes into the quarter-finals.
The Exiles will meet Cardiff Blues, who failed to reach the knockout stages this season, Edinburgh and big-spending Racing Metro in Pool 2.
Leicester have been matched with the ever-dangerous Clermont and Ulster, one of this season's quarter-finalists, with Aironi Rugby completing their group.
Aviva Premiership champions Saracens have managed to avoid any previous Heineken Cup winners, but Biarritz and Ospreys will provide challenging opposition.
Two English clubs occupy Pool Six with Harlequins and Gloucester competing with Connacht and perennial title challengers Toulouse for a spot in the last eight.
Pool 1: Munster, Northampton, Scarlets, Castres. Pool 2: Cardiff Blues, London Irish, Edinburgh, Racing Metro. Pool 3: Leinster, Bath, Glasgow, Montpellier. Pool 4: Leicester, Clermont, Ulster, Aironi Rugby. Pool 5: Biarritz, Ospreys, Saracens, Benetton Treviso. Pool 6: Toulouse, Harlequins, Gloucester, Connacht.