Study objectives: To determine whether routine performance of an ECG could have been safely avoided in a subset of emer gency department patients admitted to a university hospital. Design: Retrospective consecutive case series. Setting: University teaching hospital. Type of participants: All ED patients admitted to the medical service of the study hospital during a three-month period. Methods and interventions: Acceptable indications for an admission ECG were prospectively developed. Charts of all patients were reviewed to determine whether any of these indications were present, whether an admission ECG was performed, and whether an admission ECG resulted in a change in patient management or outcome. An ECG was classified as routine when performed in the absence of documentation of any of these indications. No interventions were performed. Measurements and main results: There were 636 ED admissions to the medical service during the study period. Of the 631 patients whose chart could be located, 384 (61%) had at least one indication for an ECG and all but one had an ECG performed. No indications for an admission ECG were identified in the remaining 247 patients; of these, 202 (82%) had an ECG per formed and 45 (18%) did not. Among the 202 who had a routine admission ECG, the test resulted in a change in management in only three (1.5%) (95% confidence interval [Cl], 0.3% to 4.3%) and affected patient outcome in none (95% Cl, O% to 1.5%). Among the 45 without indications who did not have a routine admission ECG, none experienced an identifiable adverse consequence during hospitalization (95% Cl, O% to 6.7%). Conclusion: The admission ECG could have been avoided in an identifiable subset of ED patients admitted to the medical service of our hospital, with no adverse effect on patient outcome. This finding, if corroborated in other patient populations, suggests the potential for significant cost savings for the US health care system as a whole.