Brian Cowen has been unanimously elected as Uachtarán Fhianna Fáil at a special meeting of the Fianna Fáil Ard Chomhairle.
Mr Cowen's nomination was proposed by Dermot Ahern, Minister for Foreign Affairs and Vice President of Fianna Fáil, and was seconded by Noel Dempsey, Minister for Transport and Hon Treasurer of Fianna Fáil.
Mr Cowen is the seventh President of Fianna Fáil and his appointment takes effect immediately.
In accepting the nomination, Mr Cowen told a packed National Executive meeting that becoming leader and Uachtarán of Fianna Fáil was the greatest honour of his political career to date.
Tomorrow afternoon he will become Taoiseach replacing Bertie Ahern who formerly tendered his resignation to President Mary McAleese today.
Minister for Tourism, Arts and Sport Séamus Brennan will not be a member of Mr Cowen's Cabinet.
Mr Brennan wrote to the incoming Taoiseach saying he would not be putting his name forward for consideration because of his recent health problems.
Mr Brennan praised Mr Cowen and said he would be available for a future role at his discretion in either domestic or European politics.
