Reference is made to the nosographical classification of intrathoracic goitre and the difficulties associated with its diagnosis. Particular attention is devoted to the correct surgical technique required. Surgery is mandatory in mediastinal cases on account of the slow and gradual progression of the swelling and exacerbation of the symptoms, and also because complications may supervene (cancer, intraparenchymal haemorrhage, etc.). The approach routes are discussed, along with the conditions requiring resort to a complementary route--usually median sternotomy--in addition to cervicotomy.