Details of fixture dates will be released next month. The tournament kicks-off on the weekend of 5, 6, 7 December 2003.
Cardiff regional coach David Young said,
"This is obviously a tough draw but it is what European rugby is all about. Biarritz obviously put us to the sword in France last January but people tend to forget that our young and inexperienced squad ran them very close in the first game at the Arms Park.
"With the regional squad that we are due to announce this Friday we expect to do much better next year.
"The prospect of playing Leinster and Sale is also an exciting one. All the teams in the pool play fluid, positive rugby and we can hardly wait for the matches to get underway.
"The regional team's pre-season training starts in the first week of July and we hope to play Leicester and possibly another English Premiership club in August before the Celtic League begins."
POOL 1: Stade Francais, Leicester Tigers, Ulster, Ebbw Vale / Newport region
POOL 2: Toulouse, Leeds Tykes, Neath / Swansea region, Edinburgh Rugby
POOL 3: Biarritz Olympique, Sale Sharks, Leinster Lions, Cardiff Blues
POOL 4: Agen, Northampton Saints, Llanelli region, Scottish Borders
POOL 5: Bourgoin, Gloucester, Munster, Benetton Treviso
POOL 6: Perpignan, London Wasps, Bridgend / Pontypridd region, Ghial Amatori & Calvisano