Heineken Cup champions Munster will face old rivals and former champions Leicester in the 2006/07 group stages.
Who will be celebrating in the Twickenham final next May?
Cardiff Blues and French side Bourgoin make up one of the toughest pools.
English champions Sale have Parisians Stade Francais in their group, which also includes Ospreys and Calvisano, while Wasps face Perpignan and Castres.
Top Irish seed Ulster have a fiendishly hard group with Toulouse, Scarlets and London Irish, while Leinster face Edinburgh, Gloucester and Agen.
Northampton, who finished sixth in the English Premiership, have the least demanding of the groups despite the presence of 2006 finalists Biarritz, with the Italians Overmach Parma and Scottish side the Borders making up the pool.
Leicester pipped Munster in the 2002 Heineken final, but the Irish province won at Welford Road in the quarter-finals the following year.
Munster hooker Frankie Sheehan said: "It will be tough. Leicester have been the most consistent team in Europe for the last four or five years and Cardiff finished last season very well, but hopefully we can get through it."
Leicester managing director David Clayton added: "This is a great draw for the club and its supporters and we are all looking forward to the challenge, particularly the two matches against Munster."
The first-seeded sides from each of the six nations - Biarritz (France), Treviso (Italy), Sale (England), Ulster (Ireland), Cardiff Blues (Wales) and Edinburgh (Scotland) - were drawn in separate pools.
The first round of the tournament will be played on the weekend of October 20-22, with the final at Twickenham on the weekend of 19/20 May 2007.
Pool One: Treviso, Perpignan, London Wasps, Castres
Pool Two: Edinburgh Gunners, Agen, Gloucester, Leinster
Pool Three: Sale Sharks, Stade Francais, Calvisano, Ospreys
Pool Four: Cardiff Blues, Bourgoin, Leicester, Munster
Pool Five: Ulster, Toulouse, London Irish, Llanelli Scarlets
Pool Six: Biarritz, Northampton, Parma, Border Reivers
Heineken Cup schedule:
Round One: 20-22 October
Round Two: 27-29 October
Round Three: 8-10 December
Round Four: 15-17 December
Round Five: 12-14 January
Round Six: 19-21 January
Quarter-finals: 30 March-1 April
Semi-finals: 21-22 April
Final: 19/20 May (Twickenham)