The descent of a cervical goiter below the plain of the thoracic inlet to become substernal in location, is fairly rare, but not exceptional, with an incidence, derived from several large series of operated patients, ranging from 1.7% to 13.1%. The importance of this particular location of the goiter is chiefly due to the fact that the thyroid is growing in a limited space with many surrounding structures, that unavoidably, sooner or later, will be compressed or strained. This provokes respiratory symptoms (such as cough, dyspnea, stridor) or difficulty in swallowing or determines a superior vena cava syndrome with venous stasis in the neck and in the upper thorax, and with facial oedema. The substernal location, that already constitutes a complication of the basic thyropathy, is further aggravated by the incidental malignant transformation of the substernal goiter or by the development of a thyrotoxicosis due to hyper-functioning intra-thoracic thyroid tissue. For all these reasons the presence of a substernal goiter represents in and of itself a precise indication for a surgical treatment. This study is aimed at examining the series of 19 substernal goiters observed at the Institution of General and Cardiovascular Surgery, University of Milan, from 1967 to 1987, particularly analyzing the progresses in the diagnostic procedures, the adopted surgical therapy and the observed complications.