Clinical guidelines have been developed recognizing pulmonary rehabilitation (PR) as a key component in the management of patients with chronic lung disease. The medical director of a PR program is a key player in every program and is a requirement for operation of the program. The medical director must be a licensed physician who has experience in respiratory physiology management. The purpose of this document is to provide an update regarding the clinical, programmatic, legislative, and regulatory issues that impact PR medical directors in North America. It describes the clinical rationale for physician involvement, relevant legislative and regulatory requirements, and resources available that the medical director can utilize to promote evidence-based and cost-effective PR services. All pulmonary rehabilitation (PR) programs must include a medical director. There are many clinical, programmatic, legislative, and regulatory issues that impact the PR medical director. The purpose of this document is to concentrate on the unique roles and responsibilities of the PR medical director.