Oregonians rejected legalization just two years ago but are all but certain to have a chance to reconsider this November.
State elections officials haven't yet validated the signatures turned in last week, but advocates submitted far more than they needed.
Neighboring Washington state began recreational pot sales today.
Oregon has long been on the leading edge of the decades-long push to loosen marijuana laws. It was the first state to decriminalize small-scale marijuana possession in 1973. Oregon was also among the first states to approve medical marijuana.
Unlike Oregon's 2012 effort, the team behind the current initiative has strong backing from many of the groups and individuals who helped bankroll the successful campaigns in Colorado and Washington.