Cardiff will host the Heineken Cup and Amlin Challenge Cup finals this season after Paris withdrew due to uncertainty over the availability of the Stade de France.
The Millennium Stadium will host the Heineken Cup final for the fifth time on 24 May 2014, whilst Cardiff Arms Park will host the Amlin Challenge Cup final the previous evening.
The first two Heineken Cup finals were played at Cardiff Arms Park in 1996 and 1997, and the Millennium Stadium has hosted European rugby's showpiece final on four occasions, most recently two years ago when Leinster beat Northampton.
ERC chief executive Derek McGrath said: "With fans from all corners of Europe set to travel to Wales next May, we see Cardiff as a hugely appealing setting for the finals weekend which has developed into one of the great events in Europe's sporting calendar.
"We will be working with the WRU, the Welsh Assembly Government, Visit Wales and Cardiff City Council to ensure that all supporters will enjoy a thoroughly positive experience.
"Cardiff has been the setting for some of the great finals in the past and in many ways, European club rugby is returning home. I have no doubt that the 2014 weekend at the Cardiff Arms Park and the Millennium Stadium will be yet another celebration of all that is good about European club rugby."
WRU chief executive Roger Lewis said: "We are delighted to have been chosen to again host the next Heineken Cup final at the Millennium Stadium in Cardiff.
"We know from experience that it will be a fantastic rugby occasion and a great opportunity for Cardiff and Wales to welcome tens of thousands of supporters.
"We will work closely with Cardiff Council and the Welsh Government to make this yet another great event which will deliver millions of pounds into the wider South Wales economy and this is great news at this challenging economic period in our history.
"There is something special about a Heineken Cup final and our events team at the stadium has a well-deserved reputation for ensuring that we deliver a spectacular atmosphere."