Premiership newcomers London Welsh will make their European Challenge Cup debut with a home game against French giants Stade Francais at the Kassam Stadium.
Welsh take on the beaten finalists from two seasons ago on 13 October, while Gloucester get the competition under way at Mont-de-Marsan two days earlier.
London Irish also travel to France to face Bordeaux-Begles two days later.
London Wasps, who won the cup in 2003, host Newport Gwent Dragons, and Bath travel to Bucharest Wolves.
Worcester are away to Spaniards Bizkaia Gernika RT in their opening match.
European Challenge Cup pools
Pool 1: Gloucester Rugby, London Irish, Bordeaux-Begles, Mont-de-Marsan
Pool 2: Perpignan, Worcester Warriors, VEA Femi-CZ Rovigo, Bizkaia Gernika RT
Pool 3: London Wasps, Newport Gwent Dragons, Bayonne, Rugby Mogliano
Pool 4: Bath Rugby, Cammi Rugby Calvisano, Agen, Bucharest Wolves
Pool 5: Stade Francais Paris, London Welsh, I Cavalieri Prato, Grenoble