While New Year revellers were still sipping champagne, the newborn believed to be the first in Ireland in 2002 was delivered in Limerick's Regional Maternity Hospital.
At seven minutes past midnight yesterday, Mr Paul McGuinness and Ms Angela Carmody became the proud parents of Aoife, who weighed 8lb 6oz.
Mr McGuinness said the couple from Kilrush, Co Clare, were "absolutely delighted. We are all feeling very tired but fine."
Another of the first babies delivered on the day the euro was born was Mary Tati, who has been named after the President, Mrs McAleese, by her Angolan immigrant parents because she is their first Irish-born daughter.
Mary was born at the Coombe Women's Hospital in Dublin at 12.52 a.m., arriving five days earlier than expected and weighing 7lb 1oz.
She is the third daughter of Mrs Ana Tati and her husband who obtained refugee status two years ago on the basis that they had fled persecution. As refugees, the Tatis are automatically allowed to live and work permanently in the State.
Mrs Tati (29), from Lucan, said she felt her first labour pains at 10.30 p.m. on New Year's Eve and arrived with her husband in the hospital at midnight. She said they chose the name Mary in honour of the President.
"I came here three years ago, and it's my first baby born in Ireland and I wanted her to have an Irish name," she said.
A total of 7,689 babies were delivered last year at the Coombe, continuing an upward trend which saw the annual total reaching its highest in two decades in 2000.
Meanwhile, in Wexford General Hospital baby Emma Rothwell was born to parents, Lorraine (32) and Angus (34), also at 12.52 a.m.
Mr Rothwell said Emma, the Enniscorthy couple's fourth child, was two days overdue.
"The way it was looking we thought she'd come along at half eleven but then nothing happened and she showed up an hour and a half later."
Mr Rothwell said stem cells from the umbilical cord were collected in case they were needed for any future treatment of his six-year-old daughter, Shauna, who has recovered from leukaemia.
In the North, Ms Nicola Starrett gave birth to a son weighing 6lb 2oz at 3.21a.m. in Belfast's Royal Victoria Hospital.