Twelve patients with severe, often incapacitating chest pain initially believed to be cardiac in origin were shown on subsequent evaluation to have chest wall syndrome. Diagnosis was suspected by the atypical nature of pain in 11 of 12 patients and confirmed by chest wall tenderness simulating the spontaneously occurring pain in all. Seven patients had chest wall syndrome in conjunction with other associated cardiac conditions. Five patients had isolated chest wall syndrome. All five had normal ejection fractions and no regional wall abnormalities on radionuclide cineangiographic studies performed during symptom-limited supine exercise, findings observed in few patients with coronary artery disease. Chest wall syndrome should be considered in all patients with chest pain, as its recognition can greatly aid in patient care.