In 2016, the Colorado legislature passed an amendment to Colorado's medical proxy law that established a process for the appointment of a physician to act as proxy decision maker of last resort for an unrepresented patient (Colorado HB 16-1101: Medical Decisions For Unrepresented Patients). The legislative process brought together a diverse set of stakeholders, not all of whom supported the legislation. Following passage of the statutory amendment, the Colorado Collaborative for Unrepresented Patients (CCUP), a group of advocates responsible for initiating the legislative process, coordinated a unique effort to engage these stakeholders in the creation of a set of voluntary guidelines to assist facilities and individual careproviders in the implementation of policies and procedures enabled by the statute. This article delineates the questions and concerns of stakeholders, describes how those issues were addressed within the guidelines, and proposes additional opportunities for research to assess the impact of the legislation in Colorado.