This paper reviews current evidence from several cardiology populations that suggests panic disorder is prevalent and underdiagnosed. Cardiology patients with atypical angina and no heart disease have a high likelihood of having panic disorder as suggested by studies of two separate cardiology populations. That they resemble psychiatric populations with panic is suggested by their positive response to alprazolam. Although evidence is less clear concerning the relationship between MVP and panic, it appears that patients referred to ECHO and found to have MVP are also likely to have panic. Three other populations deserving further study are patients with 1) pacemaker syndrome, 2) coronary artery disease with atypical angina and 3) certain arrhythmias.