Harlequins will launch the new European Rugby Champions Cup when they host France's Castres on Friday 17 October.
It replaces the Heineken Cup and will have 20 teams - seven English, six French and seven from the Pro12 league.
Premiership champions Northampton face Racing Metro 92 on Saturday 18 October while Scotland's sole representatives Glasgow Warriors face Bath at home.
On Sunday 20 October Heineken Cup champions Toulon welcome Welsh region Scarlets to the south of France.
|European Rugby Champions Cup round one fixtures|
|17 October||Pool 2||Harlequins||v||Castres Olympique|
|18 October||Pool 1||Sale Sharks||v||Munster|
|18 October||Pool 1||Saracens||v||Clermont Auvergne|
|18 October||Pool 4||Glasgow Warriors||v||Bath|
|18 October||Pool 5||Racing Métro 92||v||Northampton|
|18 October||Pool 3||Leicester||v||Ulster|
|19 October||Pool 5||Ospreys||v||Benetton Treviso|
|19 October||Pool 4||Toulouse||v||Montpellier|
|19 October||Pool 3||Toulon||v||Scarlets|
|19 October||Pool 2||Leinster||v||Wasps|
Pro12 champions Leinster are at home to Wasps in the first round of pool matches while Saracens take on Clermont Auvergne, who they beat in last season's Heineken Cup semi-final.
The European Rugby Champions Cup was launched after a long-running dispute sparked by French and English clubs' dissatisfaction with the structure of, and financial rewards from, the Heineken Cup.
The second-tier European Rugby Challenge Cup, which replaces the Amlin Cup, kicks off on Thursday 16 October when Gloucester take on Brive at Kingsholm.
The quarter-finals of both tournaments will be played on the weekend of 3/4/5 April 2015 and the semi-finals on 17/18/19 April.
The Challenge Cup final will be played at Twickenham Stoop on Friday 1 May, while the Champions Cup decider is set for the following day at Twickenham.
Both competitions will be televised by BT Sport and Sky.