As recreational marijuana expands, it is critical to develop standardized surveillance measures to study the retail environment. To this end, our research team developed and piloted a tool assessing recreational marijuana retailers in a convenience sample of 20 Denver retailers in 2016. The tool assesses: (i) compliance and security (e.g. age-of-sale signage, ID checks, security cameras); (ii) marketing (i.e. promotions, product availability and price) and (iii) contextual and neighborhood features (i.e. retailer type, facilities nearby). Most shops (90.0%) indicated the minimum age requirement, all verified age. All shops posted interior ads (M = 2.6/retailer, SD = 3.4), primarily to promote edibles and other non-smoked products. Price promotions were common in shops (73.7%), 57.9% used social media promotions and 31.6% had take-away materials (e.g. menus, party promotions). Nearly half of the shops (42.1%) advertised health claims. All shops offered bud, joints, honey oil, tinctures, kief, beverages, edibles and topicals; fewer sold clones and seeds. Six shops (31.6%) sold shop-branded apparel and/or paraphernalia. Prices for bud varied within and between stores (20-45/' eighth', ∼1/43.5 g). Twelve were recreational only, and eight were both recreational and medicinal. Liquor stores were commonly proximal. Reliability assessments with larger, representative samples are needed to create a standardized marijuana retail surveillance tool.