On 22 June 2008, during a live broadcast to participants at the final Mass of the 49th International Eucharistic Congress in Quebec city, Pope Benedict XVI announced:
"Dear friends, as this significant event in the life of the Church draws to a conclusion, I invite you all to join with me in praying for the success of the next International Eucharistic Congress, which will take place in 2012 in the city of Dublin!
I take this opportunity to greet warmly the people of Ireland as they prepare to host this ecclesial gathering. I am confident that they, together with all the participants at the next Congress, will find it a source of lasting spiritual renewal."
Full text available here
The Holy Father has also confirmed the dates of the Congress, which will be celebrated in Dublin from 10 - 17 June 2012.
Archbishop Diarmuid Martin & Cardinal Seán Brady were present in Quebec for this announcement. In their press release, they stated:
This is the second time that Dublin and Ireland plays host to the International Eucharistic Congress. The 1932 Congress in Dublin was considered an organisational success and it publicly showcased Catholic faith in the newly established State.
We live in different times now and it is our hope that the 2012 Congress will be an opportunity for the Catholic Church in Ireland to both reflect on the centrality of the Eucharist at the heart of our increasingly diverse community, and, to give renewed impetus to the living of faith.
Press Release from Irish Bishops' Conference here