A retro-oesophageal course of the right subclavian artery is referred to as "arteria lusoria". It may be related to severe compression of the trachea and oesophagus, typically resulting in impaired swallowing. The paper presents two patients with arteria lusoria, which in one patient was an aberrant right subclavian artery and in the other an aberrant left subclavian artery, originating from the right-sided aortic arch. In both cases the diagnosis was made with multi-slice computed tomography. The embryology of the anomalies and clinical status of the patients is discussed. Arteria lusoria should be considered in differential diagnosis in patients with dyspnoea and dysphagia. Multi-slice computed tomography allows this anatomical variant to be reliably visualised.