Munster will start their Heineken Cup campaign away to Edinburgh on 12 October after the times and dates for the start of the new season was confirmed.
Rob Penney's side will then welcome Premiership side Gloucester to Thomond Park a week later before back-to-back games with Perpignan in December.
The 2011 and 2012 winner Leinster get their tournament underway against Ospreys in the Liberty Stadium on 12 October before the visit of French Top 14 Champions Castres to the RDS a week later.
Leinster have moved their Round 4 game against Northampton Saints to the Aviva Stadium in December, in a repeat of the 2011 final.
Ulster have been handed a very testing opening fixture as they host Premiership Champions Leicester Tigers at Ravenhill on 11 October.
Mark Anscombe’s men will then travel to France to take on Montpellier at Stade Yves du Manoir eight days later on 19 October, before back-to-back games against Benetton Treviso. The Italian side come to Ravenhill on 7 December with the reverse fixture a week later on 14 December.
New Connacht coach Pat Lam will have a baptism of fire in the tournament as his side welcome Saracens to the Sportsground for their opening weekend fixture.
Connacht’s first European game on the road brings the squad to Parma to face familiar Italian opponents Zebre on 19 October, while there are back to back matches against Stade Toulousain in December.