Gov. John Kitzhaber signed a bill on Wednesday giving the state authority to license, inspect and audit stores selling marijuana.
Medical marijuana patients currently are required to grow the drug themselves or designate someone to grow it for them.
Dozens of marijuana dispensaries exist already, but they are not explicitly allowed and operate in a legal gray area. Authorities have moved to shut them down in some areas.
Proponents say existing businesses should be brought under state scrutiny to protect patients. Critics say the dispensaries will make it easier for criminals to abuse the medical marijuana program.