Cannabis
in Colorado

Amendment 64, now Article 18, Section 16 of the Colorado Constitution, lets adults 21 and older possess cannabis, but sources disagree on the exact limit. Several town and tourism pages still cite one ounce, while NORML puts the adult limit at 2 ounces of flower or concentrate, and one consumer guide says one ounce may be carried at a time within a 2-ounce total. Retail purchases are capped per transaction at 1 ounce of flower, 8 grams of concentrate or 800 milligrams of THC in edibles. Medical patients may generally possess 2 ounces, and a physician may recommend more where medically necessary. Larger amounts bring escalating penalties; above 6 ounces, possession is a misdemeanor punishable by up to 18 months in jail and a $5,000 fine.

Adults must be 21 or older to buy, possess or use cannabis under Amendment 64, and retailers require valid ID. People under 21 may not possess or consume cannabis unless they hold a valid medical marijuana card. The medical program, run by the Colorado Department of Public Health and Environment, admits residents aged 18 and over, and minors can also qualify with parental consent. A minor must submit two provider certifications, and at least one must come from a board-certified pediatrician, family physician or child psychiatrist. Giving or selling cannabis to anyone under 21 is illegal, and sharing it with an underage person is treated as a felony.

Adults 21 and older may grow up to six plants for personal use, with no more than three flowering at the same time. A single residence is limited to 12 plants in total, unless the grower is a registered medical caregiver. Plants must be grown in an enclosed, locked space that cannot be seen from outside, and home-grown cannabis may not be sold. Medical patients and their caregivers may also cultivate, and a physician can recommend a higher plant count based on the patient's medical needs. Growing beyond the legal limit is charged as a felony, according to NORML's summary of Colorado Revised Statutes 18-18-406. Cities and towns may impose stricter rules than state law.

Colorado divides cannabis oversight between two state agencies. The Colorado Department of Revenue regulates the retail marijuana market and adopted its first rules for it in September 2013, following the passage of Amendment 64. The Colorado Department of Public Health and Environment runs the medical marijuana registry, processing patient applications and issuing registry cards, and its Board of Health reviews petitions to add qualifying conditions. Cities and counties decide whether to allow cannabis businesses at all and may adopt rules stricter than the state's, which is why consumption and sales rules differ between places such as Denver, Steamboat Springs and Avon.

Adult-use cannabis is taxed far more heavily than medical cannabis. According to commercial guides, recreational purchases carry the 2.9 percent state sales tax plus a 15 percent retail marijuana tax and a 15 percent excise tax, with local taxes on top; one guide puts the combined burden at about 30 percent. Medical marijuana is subject only to the 2.9 percent state sales tax plus local sales tax, and is exempt from the retail and excise taxes. None of the sources gathered for Colorado are official state publications, so these rates should be treated as approximate until checked against the Department of Revenue.

Colorado allows on-site consumption only at licensed hospitality businesses. Everywhere else, cannabis must be used privately, in a home or on private property with the owner's permission. Public consumption, including on streets, in parks, bars, restaurants and outdoor cafes, and in vehicles on public property, is a petty offense punishable by a fine of up to $100 and 24 hours of community service. State law bans cannabis use in hotel rooms, landlords can prohibit it on their premises, and it is illegal on federal land, which covers national parks, national forests and many ski slopes. Denver voters approved Ordinance 300 to allow consumption in certain settings, and other towns set their own rules.

The Colorado Department of Public Health and Environment issues medical marijuana registry cards, often called red cards. A patient first sees a Colorado-licensed medical provider with valid DEA registration, who certifies that the patient has a qualifying condition. That certification is submitted to the department with the patient's application. Commercial services report that state registration usually completes within one to three business days after the evaluation. Once registered, a patient can buy from licensed medical centers, designate a primary caregiver, or grow at home within the permitted plant count. Evaluation fees are set by providers, not the state, and commonly range from $50 to $200.

Colorado keeps a defined list of qualifying conditions, and providers may certify only conditions on it. The list includes cancer, glaucoma, HIV/AIDS, cachexia, seizures, persistent muscle spasms, severe nausea, severe pain, post-traumatic stress disorder, added by Senate Bill 17 in 2017, and autism spectrum disorders, added by House Bill 19 in 2019. It also covers any condition for which a physician could prescribe an opioid, which widens eligibility considerably. Certain disabling medical conditions can be certified by providers other than MDs and DOs. Anyone may petition the Board of Health of the Department of Public Health and Environment to add a condition.

Applicants must be Colorado residents and at least 18, or a minor applying with parental consent. They need a certification from a Colorado-licensed provider with valid DEA registration, and for most conditions that provider must be an MD or DO. Minors must submit two certifications, at least one from a board-certified pediatrician, family physician or child psychiatrist. The application goes to the Colorado Department of Public Health and Environment, which issues the card. The sources gathered here do not state the current state application fee or list the identity documents the department requires, so those details are not given on this page.

Colorado medical marijuana cards are valid for one year and must be renewed annually, according to commercial evaluation services. Because the provider must confirm that the patient still has a condition on the state list, renewal requires a fresh certification from a qualifying provider, followed by a renewal submission to the Colorado Department of Public Health and Environment. The sources gathered for Colorado do not describe the renewal window, any grace period after expiry, or whether the renewal fee differs from a first application. A lapsed card ends the patient's medical purchase rights and tax advantages, and a patient aged 18 to 20 loses legal access altogether until the card is renewed.

The sources gathered for Colorado do not address telemedicine. They establish only that certifications must come from a Colorado-licensed medical provider with valid DEA registration, and that minors need two certifications, one of them from a pediatrician, family physician or child psychiatrist. Nothing in them says whether the evaluation may be done by video or phone, or whether an in-person visit is required. Patients considering a remote evaluation should confirm with the Colorado Department of Public Health and Environment that a telehealth certification will be accepted before paying a provider.

Colorado does not offer medical reciprocity. Its medical cannabis cards are available only to Colorado residents and are valid only in Colorado, and the sources gathered here describe no way of honoring cards issued by other states. Visitors 21 and older do not need one, because they can buy from licensed retail stores with valid ID, though some local guidance still cites a lower quarter-ounce purchase limit for non-residents. Visitors under 21 have no legal access. Cannabis bought in Colorado cannot be taken across state lines or through airports, and it may not be used on federal land such as national forests and ski areas.