After days of debate and delays, Ireland's lower house Dail passed the legislation by a 127-31 vote allowing limited abortion rights.
The bill authorises a termination when doctors deem that a woman's life is at risk, including in some cases of a suicide threat.
The bill had been drafted by the Irish government in the wake of the tragic death of Indian dentist Savita Halappanavar, who was denied a potentially life-saving abortion when she was found to be miscarrying.
The case re-ignited debate on the issue and has revealed deep divisions in the Catholic nation, with the parliamentary vote going on for a marathon two days.
Irish Prime Minister Enda Kenny and his coalition government pushed through the bill despite threats of excommunication from cardinals and bishops.
The bill now needs an Upper House endorsement but pro-choice and anti-abortion groups have already threatened court cases to challenge the new law.