Mediastinal goiter (MG) removal occasionally needs sternotomy, mainly in case of subaortic extension. We aimed to test the hypothesis that sternal-split may safely replace full sternotomy for MG removal (through total thyroidectomy) when thoracic access is required. We conducted a prospective observational cohort study comparing 15 subaortic MGs receiving sternal-split with 87 MGs undergoing cervicotomy alone between January 1997 and June 2009. Among 15 cases requiring sternal incision, sternal-split was extended to the angle of Louis in nine patients (60%), to the third intercostal space (IS) in one of five (20%) cases of MGs with anterior mediastinum involvement, and in five of 10 (50%) cases with posterior involvement (P = 0.6). Full sternotomy was never necessary. The median hospitalization was 5 days (range, 4-8 days) after sternal access as compared with 3 days (range, 2-4 days) after cervicotomy (P = 0.04). Complications were similar in these two study groups: one postoperative bleeding in each group and three recurrent laryngeal nerve palsies after cervicotomy (P = 0.5). There was no operative mortality, blood transfusion, tracheotomy requirement, wound infection, or persistent hypoparathyroidism. Proper extension of sternal-split to the second or third IS allows an adequate approach to both the anterior and to the posterior mediastinum, thus permitting safe management of MGs requiring thoracic access.