Cardiff Blues are appearing in their first semi-final as a region - although Cardiff RFC contested the first Heineken Cup final back in January, 1996, and also played in the 1996/97 semi-finals. More information.
Munster are appearing in their eighth Heineken Cup semi-final while Leicester Tigers are in the last four for the sixth time and Leinster the fourth occasion.
Cardiff Blues have never beaten Leicester Tigers in the Heineken Cup. They lost twice to them in the Pool stages of 2006/07, including the home game at the Millennium Stadium
Munster beat Leinster 30-9 in their only previous meeting in the Heineken Cup - in the 2006 semi-final at Lansdowne Road.
Niall Ronan and Kieran Lewis were both unused Leinster replacement in that game. They both now play for Munster.
There are as many as 18 players from the 30 who started that semi-final three years ago who could lock horns again at Croke Park: Leinster (8) Girvan Demsey, Shane Horgan, Brian O'Driscoll, Gordon D'Arcy, Felipe Contepomi, Malcolm O'Kelly, Cameron Jowitt and Jamie Heaslip; Munster (10) Ian Dowling, Ronan O'Gara, Peter Stringer, Federico Pucciariello, Jerry Flannery, John Hayes, Donncha O'Callaghan, Paul O'Connell, Denis Leamy, David Wallace.
Both Croke Park and the Millennium Stadium are new Heineken Cup semi-final venues. However, while the Millennium Stadium has staged three Heineken Cup finals, this will be the first tournament match at Croke Park - making it the 85th venue to host Heineken Cup action
Three Munster players - Ronan O'Gara, John Hayes and Donncha O'Callaghan - have appeared in a record seven semi-finals.
The 2003 / 2004 semi-finals had the greatest combined attendance of 82,500 when the ties were played at Lansdowne Road (Munster v London Wasps, 48,500) and at Stade Chaban-Delmas in Bordeaux (Toulouse v Biarritz Olympique, 34,000).
That Munster v London Wasps attendance is the tournament record for a semi-final but both Croke Park (82,300) and the Millennium Stadium (74,500) have greater capacities.
Former Scottish referee Jim Fleming - now an ERC Board member - controlled a record four Heineken Cup semi-finals. Alan Lewis, Alain Rolland (both Ireland) and Chris White (England) have each refereed three tournament semi-finals.
The only semi-final requiring extra time was the 1998 all-French clash between Toulouse and Brive. Toulouse lost that one on a 2-1 try count.
The 26 Heineken Cup semi-finals have been watched by 675,701 fans - an average attendance of 25,989.
The highest score in a semi-final has been the 37 points scored by Leicester Tigers against Toulouse in 1997 and the 37 points scored by London Wasps against Munster in 2004.
The biggest winning margin has been 27 points, when Toulouse beat Swansea 30-3 in 1996.
Two clubs have scored five tries in a semi-final, Leicester Tigers against
Toulouse (1997) and Wasps against Munster (2004).
Only one of the 26 semi-finals has failed to produce a try - Biarritz Olympique's 18-9 win over Bath Rugby in San Sebastian in 2006
Munster's John Hayes, Ronan O'Gara, Peter Stringer and David Wallace are aiming to reach their fifth Heineken Cup final.
Another Irishman, Leicester Tigers full back Geordan Murphy, is hoping to reach his fourth final by beating the Blues. Martin Corry, Ben Kay and Lewis Moody (an unused replacement in the victory over Munster in the 2001 final, are also hoping to do the same.
Munster prop John Hayes will become the leading cap holder in the Heineken Cup if he plays against Leinster. He equalled clubmate Anthony Foley's tournament record of 86 appearances in the quarter-finals and will go on to 87 in the semi-final.
Since his Heineken Cup debut for Munster against Petrarca on 19 September, 1998, he has missed only two of Munster's European matches. They were the first game of the 2001/02 campaign at home to Castres Olympique and the fifth game that season against Harlequins
Munster will join Toulouse on 101 Heineken Cup games played - and overtake them if they reach the final.
Croke Park will be the fourth Dublin venue at which Leinster have played in the Heineken Cup. Their first home game in the tournament was at Lansdowne Road against Pontypridd in front of a crowd of 4,000 in December, 1995. They won 23-22.
They then met Pau at Donnybrook in the Pool stages of the 1996/97 competition, again in front of a 4,000 crowd. They won that one 25-23. Their first Heineken Cup tie at the RDS was in October, 2005, against Bath, when 13,152 fans saw them lose 25-23.
Munster, Leinster, Leicester Tigers and Cardiff Blues (including Cardiff RFC) have been represented by:
113 players have represented Munster in 100 games
128 players have represented Leinster in 87 games
140 players have represented Cardiff Blues in 82 games
120 players have represented Leicester Tigers in 89 games
Cardiff Blues are bidding to become the first team to win every match on their way to the final since the advent of home and away Pool matches in 1998/99.
Leicester Tigers wing Scott Hamilton is hoping to emulate Rod Kafer by winning the a Super Rugby and Heineken Cup medal in consecutive years. Kafer was a Super 12 winner with ACT Brumbies in 2001 and then a Heineken Cup champion with Leicester Tigers in 20021. Hamilton won the Super 14 crown last May with Canterbury Crusaders - his third title after a Super 12 victory in 2005 and a Super 14 triumph in 2006.
In that 2006 Super 14 final Hamilton went head-to-head with Cardiff Blues skipper Paul Tito. In heavy fog it was the Crusaders who beat the Wellington Hurricanes, leaving Tito to wait until the Blues' EDF Energy Cup final win over Gloucester to win his first title.
The only Super 12/14 and Heineken Cup winners to date have been Kafer and Doug Howlett (Super 12 with the Blues in 2005 and Heineken Cup with Munster in 2008).
Leicester Tigers centre Aaron Mauger is also chasing a south/north double. He was a Super 12 and 14 winner with the Crusaders in 2000, 2002, 2005 and 2006.
Munster are the No1 ranked team in Europe and will play Leinster ranked fourth
Leicester Tigers are the No 2 ranked side and face Cardiff Blues ranked eighth
The public allocation of tickets for the Edinburgh 09 Heineken Cup sold-out in January. The two finalists club will share an allocation 15,000 which they will distribute to the fans directly.
The directors of ERC voted unanimously at a Board meeting to postpone all decisions including the release of further instalments of ERC's distributable central revenues to the six shareholder countries until 19 February next when the Board will meet again to reconsider the issue.