Abstract Purpose This study aimed to develop emergency department best practice guidelines for improved communication during patient care transitions. Basic Procedures To our knowledge, there are no specific guidelines for communication at the point of transition from the emergency department to the community. In Rhode Island, we used a multistage collaborative quality improvement process to define best practices for emergency department care transitions. We reviewed the medical literature, consensus statements, and materials from national campaigns; gathered preferences from emergency medicine and primary care clinicians; and created guidelines that we vetted with emergency medicine clinicians and other key stakeholders. Main Findings Because we did not find any guidelines that globally addressed care transitions from the emergency department, we drew from studies on patient discharge instructions and extrapolated from the evidence base available for other, related settings. Our key outcome is a set of care transition best practices for emergency departments, which can be implemented to establish measurable, communitywide expectations for cross-setting clinician-to-clinician communication. They include obtaining information about patients' outpatient clinicians, sending summary clinical information to downstream clinicians, performing modified medication reconciliation, and providing patients with effective education and written discharge instructions. Principal Conclusions The best practices provide feasible standards for evaluating and improving how patients transition out of the emergency department and can provide a framework for emergency department leaders expanding their collaboration with community partners, particularly in the context of emerging payment models. They also catalyze introspection and debate about how to improve communication and accountability across the care continuum.