The full House passed the bill by a vote of 31-19.
The bill would allow same-sex and heterosexual couples to enter into civil unions and receive the same rights, benefits and responsibilities as marriage under state law.
Last month, the state Senate passed the civil unions bill by a vote of 19-6.
But because of amendments attached in the House at the recommendation of the state Attorney General’s Office, the bill will now go back to the Senate before making its way to the Governor for his signature.
Democratic Gov. Neil Abercrombie has promised to sign the civil unions legislation if approved, calling it a simple issue of civil rights.