The all-French semi-final between Stade Francais Paris and Biarritz Olympique will be staged on Saturday, 23 April at the 45,000 capacity Parc des Princes in Paris, kick-off 16:00.
The clash between former double champions Leicester Tigers and Toulouse - who between them have won European club rugby's most coveted trophy four times in nine seasons - will be the first rugby union match played at the Walkers Stadium, home of Championship side Leicester City FC.
Parc des Princes, the former home of French rugby, has staged the 2001 Heineken Cup final and Stade Francais Paris' quarter-final victory over Newcastle Falcons last Saturday 2 April.
Both Leicester Tigers and Stade Francais Paris were drawn out first in the Heineken Cup semi-final draw, which took place in Edinburgh on Tuesday, 28 January, 2005.
Over 77,000 fans will be able to attend the two much anticipated games. ERC is keen to attract as many fans from both teams as possible and therefore will provide a marketing budget to each of the four semi-finalists to assist in maximising their support.
"We are delighted to confirm two excellent venues for the semi-finals after a superb weekend of quarter-final matches in France, Ireland and Spain," said Jean Pierre Lux, ERC Chairman.
"Each of the quarter-finals attracted capacity attendances with over 162,000 fans enjoying four fantastic sporting occasions last weekend. The Heineken Cup has really captured the imagination of fans across Europe and the semi-finals are again set to be played in front of capacity crowds."
Both semi-finals will be broadcast live on television by ERC's broadcast partners.
Ticket information will be announced shortly on http://www.ercrugby.com/
HEINEKEN CUP 2005 SEMI-FINALS
(Kick-offs LOCAL time)
Saturday 23 April - Parc des Princes, Paris (45,000)
16.00 Stade Francais Paris v Biarritz Olympique (FR2 / Sky Sports)
Sunday 24 April - Walkers Stadium Leicester (32,000)
15.30 Leicester Tigers v Toulouse (Sky Sports / Sport + / RTE)