To determine the utility of preoperative screening electrocardiograms (ECGs) among ambulatory surgery patients, we reviewed the charts of 751 consecutive adult patients who underwent ambulatory surgery. Data were collected on demographic characteristics, coexisting medical problems, American Society of Anesthesiologists physical status score, preoperative ECG results, adverse intraoperative cardiovascular events, and postoperative cardiovascular complications. In our study population of relatively healthy outpatients, preoperative ECGs were abnormal in 42.7% of patients. Age, increased physical status score, and male gender were associated with a greater incidence of abnormal preoperative ECGs. There were 12 adverse cardiovascular perioperative events among the 751 patients (1.6%), and the preoperative ECG may have been clinically useful in six of these 12 patients. Neither preoperative ECGs nor results of preoperative screening questionnaires were predictive of adverse cardiovascular perioperative events. These findings question the utility of preoperative ECGs in the ambulatory surgery setting, especially among younger, relatively healthy patients.