[2] The structure of the competition was a purely knockout format; teams played each other on a home and away basis, with the aggregate points winner proceeding to the next round.

Castres Olympique secured a victory over Caerphilly in the final and picked up their first piece of European Club silverware.

[2] Castres Olympique Grenoble Mont de Marsan Pau Gran Parma L'Aquila Overmach Parma Petrarca Padova Rugby Roma Rovigo Rugby Silea Dinamo București La Moraleja UC Madrid Caerphilly Ebbw Vale This competition was contested between 12 first round losers from the 2003–04 European Challenge Cup plus 4 other Clubs entering directly into the 1st Round.

[2] Rotherham Montpellier Gran Parma L'Aquila Leonessa Overmach Parma Petrarca Padova Rugby Roma Rovigo Viadana El Salvador Valladolid RAC AA Coimbra Clube Rugby Lisboa UC Madrid UE Santboiana This competition was intended to be contested between 12 first round losers from the 2004–05 European Challenge Cup, plus 4 other Clubs that joined directly at the 1st Round of the Shield.

Auch secured a victory over Worcester Warriors in the final and picked up their first piece of European Club silverware.