Fifty-eight consecutive patients were investigated for spontaneous chest pain without symptoms of effort angina, previous myocardial infarction or other signs of cardiac disease, to determine the incidence of oesophageal spasm. The character of the chest pain, its context and the results of resting ECGs were analysed. An ECG recorded during chest pain was available in 23 cases and exercise stress testing was performed in 43 cases. Coronary angiography was carried out in all patients. The coronary arteries were normal or showed little change in 44 patients. Further investigations were ordered: oesophageal manometry (42 cases), echocardiography 44 cases) and ergometrine provocation tests (44 cases). The patients were then divided into 4 groups: 23 patients (40 p. 100) with coronary artery disease; either atheroma (14 cases) or spasm (9 cases); 8 patients (13,5 p. 100) with non-coronary cardiac pathology (myocardial hypertrophy or mitral valve prolapse); 15 patients (26 p. 100) with oesophageal spasm alone; 12 patients (20,5 p. 100) with no obvious organic disease. Often simulating spontaneous angina, clinically and electrocardiographically, oesophageal spasm may sometimes be distinguished (6 out of 15 cases) by the finding of painful dysphagia on swallowing ice-cold liquid. The condition is confirmed by oesophageal manometry which shows abnormalities of oesophageal contraction. In addition, 13 out of 15 patients in our series had hypotonia of the gastro-oesophageal sphincter. Dyskinetic phenomena and this hypotonia should be taken into consideration in the treatment of this condition.