Thirty-one patients with thoracic outlet syndrome have been studied in detail in the neurological and vascular clinics at this hospital. The patients were classified on the basis of their presenting symptoms into four groups--predominantly vascular, neurological, combined vascular and neurological, and pain and paraesthesiae alone. The majority of patients had radiological abnormalities and all had structural lesions in the superior thoracic aperture seen at operation. All operations were carried out through a standard supraclavicular approach, enabling the compressive structures to be visualized. This would not have been the case had the commoner trans-axillary approach for first rib resection been followed and in fact none of the operations included removal of the first rib. The results of operation were evident in our patients with a marked relief in their vascular symptoms, their pain and paraesthesiae and a slight but definite improvement in muscle bulk and power.