Introduction: In a busy emergency department (ED), effective communication is integral to the provision of safe medical care. Physicians working in the ED interact with multiple team members including patients, allied healthcare professionals and other physicians, who all need to understand their verbal and written instructions. Our study's objective was to identify and describe communication problems occurring in the ED setting, and how these problems contributed to patient safety events and increased medico-legal risk for physicians. Methods: The Canadian Medical Protective Association (CMPA) is a not-for-profit, medico-legal organization which represented over 97,000 physicians at the time of this study. We conducted a retrospective descriptive analysis where we extracted five years (2013-2017) of CMPA data describing closed medico-legal cases occurring in the ED involving physicians (any specialty) who experienced complaints due to communication issues. We then applied an internal contributing factor framework to identify data themes. Data were summarized using descriptive statistics. Results: We identified 517 eligible cases involving 521 patients (some cases involved >1 patient). We found that 99.8% (520/521) of patients experienced some form of healthcare-related harm in the ED. Specifically, there was poor communication between: the physician and patient or patient's family (202/517, 39.1%); two or more physicians (79/517, 15.3%), and physicians and other healthcare providers (55/517, 10.6%). Inadequate documentation was observed in more than half of the cases (324/517, 62.7%) and poor team communication affected physicians’ decision making process (326/517, 63%) in areas such as deficient assessments, inadequate investigations, failure or delay to attend to the patient, and disposition decisions. Conclusion: Team communication issues are prevalent among physician medico-legal cases occurring in the ED. Efforts to strengthen communication skills may enhance patient safety and reduce medico-legal risk.