This paper reviews current evidence from several cardiology populations that suggests that 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. A panic disorder subtype, called non-fear panic disorder also appeared in about one-third of these cardiology panic patients. These patients have most of the panic symptoms but do not report fear during their episodes.