Complete or partial absence of the pericardium is a relatively rare disorder. While physical examination, electrocardiogram, and chest x-ray may suggest the diagnosis, definitive noninvasive diagnosis has until recently not been possible. In the patient described in the present report, the basis for chest pain initially attributed to myocardial ischemia was established noninvasively by computed tomographic examination of the chest to be congenital absence of the left pericardium. Experience with this patient emphasizes the fact that one of the known bases for nonischemic chest pain--congenital pericardial defects--can be precisely defined by contrast-negative computed tomographic imaging.