SummaryIntrathoracic goitre is one of the rare, benign causes of potentially curable superior vena cava syndrome (SVCS). We report two cases of colloid in trathoracic goitre responsible for SVCS, as confirmed by simultaneous thyroid scanning and isotopic superior cavography. Both patients underwent surgical excision of their goitre and had a complete cure of their superior vena cava syndrome. This report illustrates the importance of considering be nign etiologies of superior vena cava syndrome be fore starting emergency radiotherapy.