In 2014, to much fanfare, Colorado implemented the world’s first legal and regulated seed-to-sale cannabis market for adults. The Retail Marijuana Code (RMC) was built on established medical cannabis regulations and multi-stakeholder collaboration. As a commercial model, the approach is not ideal from a public health perspective, although strict regulation has some advantages over continued criminalisation of cannabis. The chapter consists of three parts. Part 1 includes: (i) latest market insights around patterns of consumption in the State; (ii) a brief review of the emerging literature on the CRCM; (iii) the public health framework employed in Colorado; and (iv) a summary of the Retail Marijuana Code (RMC) and its evolution. In Part 2, tensions between public health and commercial profit are explored with a focus on: (i) constitutional constraints on public health best practice; (ii) marketing and advertising, most notably at the coal face of regulating controls by for-profit firms; (iii) budtenders, the sales people in retail stores; and (iv) the public health risks associated with the application of chemical pesticides for protection of commercial crops. Part 3 brings the material together to highlight important lessons learned from the CRCM for regulators in other jurisdictions considering the legalisation of cannabis for adult use.