This evening at his official residence in the Phoenix Park, President Michael D Higgins signed off the Thirty-fourth Amendment of the Constitution (Marriage Equality) Bill 2015.
This means that the result of May's historic referendum has now been enshrined in law.
A number of legal challenges brought against the result meant tonight's signing was delayed somewhat, but all the disputes were struck down at earlier High Court hearings.
The Irish people had voted by a margin of 62-38 percent and marriage in this country may now take place between two persons "without distinction as to their sex".
The Bill will also be introduced to the Dáil next month.
Although it was originally hoped that the first marriages between same-sex partners could take place as early as next month or October, it seems more likely now that those ceremonies will be held towards the end of this year.