This analysis of 31 cases of anomalies of the aortic arch has confirmed the predominance of subclavian retro-oesophageal arteries and double aortic arches (74% of cases). The age at which the first clinical signs presented was less than one year in 75% of cases. Respiratory signs predominated with recurrent bronchitis (16 cases) and bronchial congestion (9 cases). These signs were not specific for the type of aetiology and were characterised by their chronicity and recurrent nature. Inspiratory and expiratory stridor was found on 8 occasions and was very suggestive of the diagnosis. There was a frequent association of asthma and anomalies of the aortic arch in this series (13 cases) with 6 cases of atopic asthma in early childhood and 7 cases of asthma in infancy. The oesophago-gastroduodenal transit was the key diagnosis which enabled the vascular anomaly to be confirmed. There was, however, a failure on 5 occasions with 2 false negatives and 3 cases where the wrong type was suspected. Fibreoptic bronchoscopy enabled the topography to be established more precisely including the degree of compression (in 14 cases) and showed evidence of associated tracheomalacia in 7 cases. Nuclear magnetic resonance was very helpful, giving a better definition of the anatomical type and of the relationship of the vascular arch with the oesophago-tracheal axis. Broncho-fibroscopy and nuclear magnetic resonance make strong contributions towards the indications for operation.