Next year's election, due to be held in June, will see Islanders electing 37 Deputies in nine newly formed voting districts, no Senators and 12 Constables.
States Members voted overwhelmingly to support a proposition from the Privileges and Procedures Committee, by 31 votes to 12, with no abstentions.
PPC chair Carina Alves said: 'I do believe we are making positive changes for our Island and the people we represent.'
Deputy John Young called it the 'most progressive and major reform that has happened for decades'.
Members also voted to move the date of next year's election to 22 June.
Another amendment from Senator Gorst to save the Senatorial seats was rejected on Wednesday.
Full story in Friday's JEP.