Former Labour Party TD Declan Bree will contest the general election under the United Left Alliance umbrella.
Mr Bree, who served as a TD between 1992 and 1997, has also served as a councillor and as mayor of Sligo.
"The United Left Alliance, is a real alternative to the mainstream political establishment who are all committed to the same policies of cutbacks and austerity. The main opposition parties, Fine Gael and Labour, can only offer more of the same tired, old-style, crony type politics", Mr Bree said in Dublin today.
He said the Alliance is "committed to putting the interests of people first by ending the bank bailouts and reversing the savage cuts to pay, social welfare and public services".
Mr Bree, who was first elected to Sligo Corporation and Sligo County Council in 1974, resigned from the Labour Party in 2007 citing differences with the then leadership of Pat Rabbitte.
At the time of his resignation, he said he had major difficulties with the "ill-conceived decision" of the Labour Party to enter into a pre-election agreement with Fine Gael ahead of the 2007 general election.
The United Left Alliance has 20 candidates in 19 constituencies across the country.