In 2004, 62 percent of Montana voters approved the Montana Medical Marijuana Allowance (I-148), allowing registered patients with a qualified condition to use, possess, and cultivate medical cannabis and designate a caregiver to assist them. In 2011, the Montana legislature passed legislation (SB 423) repealing many of the provisions of I-148. SB 423 became the subject of a lengthy court challenge, with the Montana Supreme Court ruling in 2016 to uphold most of the provisions of the law.  That same year Big Sky Country voters approved I-182, which not only restored many of the rights granted to patients in I-148, but also added PTSD and removed restrictions on chronic pain for qualifying conditions. 

Governor Bullock signed SB 333 into law in 2017, authorizing mandatory testing of medical cannabis products to improve patient safety, seed-to-sale tracking of all licensed cannabis plants in the supply chain, and imposing a 4 percent tax on medical cannabis that was reduced to 2 percent in 2018.  The tax was later increased to 4 percent to assist with program funding.  In 2019, Montana enacted SB 265, which made improvements to laboratory testing, telemedicine and removed the requirement that patients must only obtain medicine from a single dispensing facility.  This is a noteworthy program improvement, offering patients much greater access flexibility and consumer choice.