Two groups were working to advance initiatives to put legalization on the ballot for November's election.
On Thursday, Arkansans for Responsible Medicine withdrew their initiative.
The other group, Arkansans for Compassionate Care, is pleased to be the only group still collecting signatures.
In a statement sent to KNWA/Fox 24, ACC Campaign Director Melissa Fults said in a statement:
"We are delighted that the confusion over the 2014 medical cannabis initiative has ended. Two initiatives would have only hurt the cause. We can safely move forward in our signature drive, get on the ballot and give Arkansans the option of using medical cannabis."
Fults' group has until July to collect the 62,507 signatures to be on the ballot.