Alan Kelly is the new Labour Party leader.
The Tipperary TD was formally announced the winner of the leadership contest late last night.
Out of a total valid vote of 1,915 votes, Deputy Kelly received 1,047 votes compared to 868 received by Deputy Ó Ríordáin
Brendan Howlin quit the role after the party's poor showing in the general election.
Alan Kelly's chief rival, Dublin-based Aodhán Ó Ríordáin conceded defeat via Twitter.
In a video online, he said the party had a lot of work to do.