North Dakotans will vote on the medical marijuana issue in November.
The Secretary of State says supporters turned in more than 17,200 qualified signatures.
They only needed 13,500 to get on the ballot.
With voters' approval, the initiative would make it legal for people to possess up to 3 ounces of marijuana for medical purposes.
Those who qualify could obtain the drug from a state-licensed dispensary or grow a limited supply for personal use.
In South Dakota, a judge this week denied an appeal to get a medical marijuana measure on the ballot.