Objectives: The authors examined the ability of emergency physicians (EPs) to recognize adverse drug-related events (ADREs) in elder patients presenting to the emergency department (ED). Methods: This was a prospective observational study of patients at least 65 years of age who presented to the ED. ADREs were identified using a validated, standardized scoring system. EP recognition of ADREs was assessed through physician interview and subsequent chart review. Results: A total of 161 patients were enrolled in the study. Thirty-seven ADREs were identified, which occurred in 26 patients (16.2%; 95% confidence interval [CI] = 10.5% to 22.0%). The treating EPs recognized 51.2% (95% CI = 35.2% to 67.4%) of all ADREs. There was better recognition of those ADREs related to the patient's chief complaint (91%; 95% CI = 74.1% to 100%) as compared with recognition of ADREs that were not associated with the chief complaint (32.1%; 95% CI = 14.8% to 49%). EPs recognized six of seven severe ADREs (85.7%), 13 of 23 moderate ADREs (56.5%; 95% CI = 36.8% to 77%), and none of the mild ADREs. Recognition of ADREs varied with medication class. Conclusions: EP performance was superior at identifying severe ADREs relating to the patients' chief complaints. However, EP performance was suboptimal with respect to identifying ADREs of lower severity, having missed a significant number of ADREs of moderate severity as well as ones unrelated to the patients' chief complaints. ADRE detection methods need to be developed for the ED to aid EPs in detecting those ADREs that are most likely to be missed.