Businessman Peter Casey is to contest the European elections in the Midlands-Northwest constituency, after registering his candidacy at Castlebar courthouse this afternoon.
Launching his campaign, the independent candidate said he would be "the voice for rural Ireland" at the heart of the EU, if elected.
Peter Casey contested the Irish presidential elections last year, and polled second to incumbent Michael D Higgins.
The Derry native, who lives in Donegal, is founder and former executive chairman of Claddagh Resources, a global recruitment business and a former Dragon's Den investor.
He says rural Ireland needs a catalyst for change, having borne the brunt of austerity.