Brian Cowen is not expected to have much of a political honeymoon
Outgoing Irish finance minister Brian Cowen has formally taken over from Bertie Ahern as taoiseach.
The 48-year-old was elected in the Irish Parliament and won by 88 votes to 76. He was given a standing ovation by party colleagues in the Dáil.
Fine Gael Leader Enda Kenny said Mr Cowen had assumed position as captain of the team of Ireland and he urged him to use his position wisely.
Mr Ahern handed in his seal of office to President McAleese on Tuesday.
As prime minister, Mr Cowen succeeds Mr Ahern as Fianna Fáil leader and head of the coalition government.
His first electoral test is just weeks away, with a referendum on the Lisbon Treaty which reforms the EU.
Focus on finances
The Republic of Ireland is the only country holding a referendum on the issue.
All the main political parties with the exception of Sinn Fein are urging a yes vote, but the polls show growing support for those opposed, especially in the farming community.
Mr Ahern, 56, was taoiseach since June 1997 and has been a member of the Dáil or Irish Parliament for 31 years.
He announced on 2 April that he would be stepping down, amid mounting pressure as a public inquiry investigating planning corruption in the 1990s questioned him about his personal finances.
Mr Ahern said he had not done anything wrong, but was quitting because he did not want the constant focus on his finances to affect his Fianna Fáil party.