OBJECTIVE: Emergency department (ED) chest pain protocols often include an exercise stress test (EST) in an outpatient setting to further risk stratify patients initially identified as low risk for acute coronary syndrome. Our goal was to characterize the noncompliant patient population and delineate reasons for uncompleted EST. METHODS: We conducted retrospective chart review of all ED-scheduled ESTs over a 6-month period. Demographic and compliance information was abstracted using standardized instrument, a 1-month consecutive patient subset was identified, and a telephone interview was conducted with noncompliant patients to determine why they did not complete their EST. RESULTS: From January to July 2007, 57% (378/668) of patients were noncompliant with the ED-scheduled EST. In the subset, 78% (78/100) did not complete the EST: 58 patients never showed for their scheduled EST and 20 patients showed but could not initiate the EST because it was deemed inappropriate by health care workers in the cardiovascular laboratory or they began the test and it was nondiagnostic. Noncompliant patients were more likely to be male, unmarried, African American, and uninsured compared to compliant patients (P < .05). The most commonly stated reasons for noncompliance were miscommunication, financial, or inconvenience of scheduled time. Employed patients were more likely to state financial reasons for noncompliance, whereas unemployed patients were more likely to state personal reasons (P < .05). CONCLUSIONS: Our findings suggest lack of patient comprehension about purpose and logistics of EST completion. Based upon our data, the ED should confirm the appropriateness of the EST for each patient and improve patient communication and EST availability.