Four patients with elevated creatine phosphokinase (CPK) values and recurrent chest pain were found to have thoracic outlet syndrome. This association of abnormal CPK levels and chest pain due to thoracic outlet syndrome has not been previously reported. Symptoms and CPK values improved with anti-inflammatory medications and/or proper posture instruction. It is proposed that CPK values become elevated by ischemic or neurologic compromise of muscles supplied by the subclavian artery or brachial plexus respectively. Accordingly, chest pain in the same dermatomal distribution as that of angina pectoris may be simulated by ischemic skeletal muscle. Thoracic outlet syndrome therefore should be suspected in any patient with chronically abnormal CPK values and chest pain in whom no other etiology can be determined.