Fianna Fáil Senator Denis O' Donovan has been voted Cathaoirleach of the Seanad by 44 votes to six.
He was supported by Fine Gael, number of Independents and Labour. Mr O' Donovan received a standing ovation.
His appointment was expected following a deal between his party and Fine Gael as part of the minority Government agreement.
Sinn Féin Mayo Senator Mary Conway was her party's nominee but was defeated by 43 votes to 8. Independent Senator Frances Black voted with the seven Sinn Fein Senators.