The bill passed in the Dail yesterday without a vote and justice minister Dermot Ahern said the move reflected change in Irish society.
"Our society has change substantially in recent decades,’’ he said.
“While marriage is more popular than ever, other forms of relationships have become increasingly common; they create some difficulties in the legal system and require in our law a measure of recognition and of protection."
Irish gay campaigners welcomed the bill’s progress but reiterated concerns that some areas of the law were not covered.
Kieran Rose, the chair of the Gay and Lesbian Equality Network, called it a "major civil rights reform and a great achievement for Irish society".
But he added: “A continuing area of concern for GLEN however, is the absence in the bill of support and recognition of the many children being parented by same-sex couples. This critical omission will have to be addressed.”
The rights the bill will give include protections and obligations across areas such as protection of the couple’s shared home, domestic violence, residential tenancies, succession, refugee law, pensions, taxation, social welfare and immigration.
All parties supported the bill, although some individual politicians attacked it.
It is expected to become law in the autumn, 17 years after Ireland decriminalised homosexuality.
The bill will go to the upper house (Seanad) in the next two weeks, which has limited power but can send it back to the lower house. Once passed by the Seanad, the president signs the bill into law.