In a recent study, the authors reported that 25% (108/441) of consecutive emergency department (ED) chest pain patients had panic disorder (PD). As part of this study, the authors sought to answer the question: How do ED patients with PD compare with patients with PD who seek treatment in a psychiatric setting? PD patients from an ED (n = 108) and psychiatric clinic (n = 137) were compared with respect to comorbid Axis I diagnoses, self-report scores, and recent suicidal ideation. The group of psychiatric patients was younger (36.5 vs. 52.3 years) (P < 0.0001) and consisted of proportionally more women (63% vs. 39%) (P = 0.0001) than the ED patients. The psychiatric patients had significantly higher rates of comorbid agoraphobia (100% vs. 15%) (P < 0.0001), social phobia (23% vs. 3%) (P = 0.0001), specific phobia (12.3% vs. 4.6%) (P = 0.03), and posttraumatic stress disorder (16.9% vs. 5.6%) (P = 0.006), compared with the ED patients, and displayed significantly higher scores on all of the self-report panic measures. However, the patients in both groups had similar rates of comorbid generalized anxiety disorder (41.2% vs. 33.3%) (P = 0.17), major depression (8.8% vs. 11.1%) (P = 0.54), and obsessive-compulsive disorder (1.5% vs. 2.8%) (P = 0.7). Both groups also did not differ on the Beck Depression Inventory and in their rate of report of recent suicidal ideation (32% vs. 25%) (P = 0.23). Both psychiatric and ED patients with PD appear to be highly distressed patients who require treatment. Early intervention for ED patients may prevent both chronic patient distress and development of the significant phobic avoidance observed in psychiatric patients.