The Hawaii House of Representatives approved a civil union bill yesterday, which will now go to the governor for approval.
The bill was voted through 31-to-20 and passed the Senate earlier this year.
Republican governor Linda Lingle has so far given no indication as to whether she will sign it.
The bill easily passed the legislature last year but stalled when Democrats feared they would not have enough votes to override a governor veto.
If passed, it will give same-sex couples in the US state all of the rights and benefits of marriage.
Hawaii restricts marriage to heterosexual couples.