Legislation History

The Colorado Marijuana Legalization Amendment, also known as Amendment 64, was approved by voters on November 6, 2012, passing with 55.3% of the vote. Amendment 64 legalized recreational cannabis for adults 21 and older, and established sales and cultivation taxes. Before approval of Amendment 64, the possession or use of cannabis was reserved for qualifying patients and their caregivers.


Medical cannabis has been legal in the Centennial State since 2000, when voters approved Initiative 20. It passed with 53.5% of the vote. Initiative 20 permitted medical marijuana and created an identification card system for patients and their caregivers.


Colorado’s adult-use marijuana industry is regulated by the Colorado Department of Revenue (CDOR). The CDOR also provides regulatory oversight and licensing for medical marijuana production, distribution, testing, and sales.

The Colorado Medical Marijuana Registry is regulated by the Colorado Department of Public Health and Environment (CDPHE).

Where is it Safe to Purchase?

Adults 21 and older and medical marijuana patients may purchase cannabis from any state-licensed dispensary. If patients are unable to make the transaction themselves, they may also designate a caregiver to purchase and deliver medical marijuana on their behalf. Patients may purchase from exclusively medical marijuana dispensaries.

There is a 15% retail sales tax on all sales of retail marijuana and retail marijuana-infused products. A 2.9% sales tax only applies to the sale of medical marijuana and medical marijuana products.

Where is it Safe to Consume?

Colorado prohibits consumption of cannabis openly or publicly. Cannabis consumption is reserved for private, personal use in locations not open or accessible to the public. It is illegal to use or consume cannabis in a motor vehicle, and it is illegal to drive under the influence of cannabis.


Adults 21 and older may possess up to one ounce (1 oz), or 28.5 grams, of dry cannabis or cannabis-infused products, and 8 grams of marijuana concentrates. Qualifying patients and their caregivers may legally possess up to two ounces (2 oz), or 57 grams, of usable cannabis. Adults, qualifying patients and their caregivers may each grow or possess a maximum of six (6) plants, with three (3) plants in the flowering stage, and a total of 12 plants on a residential property.


Caregivers must provide the location of each cannabis cultivation site and the registration number of each patient they serve. If any patient qualifies for an extended plant count, those plants and their corresponding patient registry numbers must be registered with the CDOR. The specific laws regarding cultivation and patient plant counts vary by city and county. However, parent caregivers cultivating fewer than 36 plants are not required to register with the Caregivers Registry.


Only homebound patients may designate a transporting caregiver. When registering, transporting caregivers must provide the registry personal identification number (PIN) of each homebound patient, the total number of plants and quantities that the caregiver is authorized to transport. Additionally, transporting caregivers must also provide location of each patient’s registered medical marijuana center or caregiver cultivation site, if applicable.


Adults may gift up to one ounce (1 oz), or 28.5 grams, of usable cannabis.

How Old Do I Need
to Be to Consume?
Possession Limit
for Flower
Possession Limit
for Concentrates

Medical Marijuana Registry

The Colorado Medical Marijuana Registry is a statewide program that allows patients with qualifying medical conditions to receive a registry ID card for legal access to medical marijuana. Registry ID cards are available to Colorado residents only, and must be renewed yearly.


The Colorado Medical Marijuana Registry established a state-authorized ID card, along with an online database used to tack and verify qualified patients and their designated caregivers. Patients and caregivers must each apply for a card for a registry card themselves. Minors must apply with a parent or legal guardian and must designate two caregivers.

Qualifying Conditions

  • Cachexia, or wasting syndrome
  • Cancer
  • Glaucoma
  • Persistent muscle spasms
  • Post-traumatic stress disorder (PTSD)
  • Seizures
  • Severe nausea
  • Severe pain

Application Process

  1. Obtain a physician’s recommendation.
  2. Submit a valid Colorado driver’s license or ID to establish residency.
  3. Designate a caregiver and submit a valid caregiver’s registration ID, if applicable.
  4. Designate cultivation status.
  5. Pay a $25 Medical Marijuana Registry Identification card fee.


Caregivers are required to register annually with the CDOR Caregivers Registry to transport or grow cannabis on behalf of a patient. Caregivers must be at least 18 years old and be a permanent resident of Colorado. Caregivers can follow one of these four designations:

  • Cultivating: grows marijuana on behalf of patients.
  • Transporting: transports marijuana for homebound or minor patients.
  • Parents of a minor patient: Parents or legal guardians of a patient younger than 18.
  • Advising: Advises patients on the medicinal use of marijuana.


Colorado allows any adult with a government-issued ID to purchase cannabis from a recreational dispensary if they are 21 or older. Colorado does not offer reciprocity; out-of-state patients cannot purchase from medical marijuana dispensaries.

Lab Testing

The CDOR requires that all cannabis harvested for commercial medical and adult-use must be tested to meet certain quality and safety control standards. There are four lab certification types, which may be obtained in the course of a CDOR facility inspection.

  • Potency testing
  • Microbial (bacteria and fungi)
  • Residual solvents
  • Metals


The CDOR offers online applications for retail marijuana establishments. Business owners and investors may need to submit additional applications. Medical marijuana licenses also go through the CDOR, even though the patient registry is maintained by the CDPHE.


This page was last updated on November 5, 2018.