Enda Kenny said he was "glad" the pontiff would visit the country for the World Meeting of Families in August 2018.
In May this year the Pope confirmed the meeting would take place in Dublin with the theme of "The Gospel of the Family: Joy for the World" but Francis did not say if he would attend.
Following a 23 minute meeting with the clergyman Mr Kenny confirmed he would visit the country.
Pope Francis was, he said, "an important voice for the young, the poor and disadvantaged".
Northern Ireland's Deputy First Minister Martin McGuinness said there was "no prospect" of him not crossing the border.
"I think there is no prospect whatsoever of him coming to Ireland and him not coming to the North," he said.
Asked how why he was so sure, he replied: "Because I'm around a long time and I know how these things work."
