The diagnostic features and operative results in 13 patients with subclavian artery aneurysms were analysed. Symptoms related to subclavian artery aneurysms were present in seven patients, whereas six patients were asymptomatic and the aneurysm was discovered incidentally on chest X-ray. Angiography was the most valuable diagnostic examination and was also necessary in planning the operation. A correct preoperative diagnosis was made in five of six patients with computed tomography. Resection of the aneurysm was performed in nine and aneurysmal exclusion in the latest four patients. Direct reconstruction was used in nine and in four cases an extra-anatomic carotico-subclavian bypass was performed. Postoperative complications arose in two symptomatic and in four asymptomatic patients (46%: two strokes, two wound infections demanding extirpation of the prosthesis in one patient, two pareses of the recurrent nerve and one postoperative haemorrhage). Operative mortality was one patient. Follow-up data was available for all patients for periods of 6 months to 14 years. The vascular graft was patent in all patients. The authors conclude that subclavian artery aneurysm must be included in the differential diagnosis of all obscure upper mediastinal masses as seen on the chest X-ray and examined with CT and angiography. Exclusion of the aneurysm with extra-anatomical reconstruction is technically easier and gives the same postoperative long-term results as resection of the aneurysm and direct reconstruction. A relatively high complication rate after operation on asymptomatic subclavian aneurysms indicates a need for re-evaluation of operative indications in asymptomatic patients.