Background: During upper mediastinal surgical interventions, innominate vessels may be ruptured inadvertently or divided intentionally by the surgeon for a better exposure. The question, whether a divided innominate artery or vein should be reconstructed or not, has not yet been clearly answered. Materials and Methods: In a retrospective study, 11 patients who underwent surgery between 1996 and 2004 in our department (7 females & 4 males) with mean age of 38.7 years old were found undergoing an upper mediastinal surgery with ligation of a great vessel. Fourteen great vessels (6 innominate arteries, 4 left innominate veins, 3 right innominate veins and one right carotid artery) were ligated with no reconstruction. The vessels were intentionally divided for a better exposure or ligated for controlling of severe bleeding (due to an iatrogenic trauma) in 6 and 5 patients, respectively. Results: One patient with innominate artery and right innominate vein division suffered from a 48 - hour period of coma due to a cerebral edema which was completely resolved. Two patients developed infection at the site of sternotomy and were managed with antibiotics and wound care. No complication occurred in the remaining. In two cases with division of innominate arteries, the peripheral pulses disappeared, but there was no muscle weakness, or ischemic pain in the limb. The follow-up period was between 2-96 months (mean; 24.8). Conclusion: In critical condition and when surgical situation is not suitable for reconstruction, innominate vessels could be safely ligated and divided for a better surgical exposure and control of bleeding; with acceptable post-op risks. (Tanaffos 2004; 3(10): 19-23)