Hiring is starting immediately for 450 jobs at eBay in Dundalk.
The jobs will be created gradually over three years, but 110 new staff are needed now.
eBay owns Pay Pal, which announced last February that they were setting up a European base in Dundalk.
Jobs Minister Richard Bruton said the news was great for Dundalk, and for Ireland.
"They are quality jobs and they show an economy in transition," he said.
"Ireland has undertaken a very difficult change, but that change is now happening. Last year the IDA had its best year in a decade (and) we're growing our exports to record levels.
"Today's announcement shows that the transition that we're working on is delivering, and in really significant ways."