Until recently, the cranial base tumors were deemed unresectable due to the inability to diagnose the extent of the involvement accurately and to approach and excise the tumor safely. With refinements in CT and NMR scanning and development of craniofacial techniques, reconstruction becomes absolutely crucial in allowing successful resection of these tumors. Resection of these tumors may sometimes result in massive and complex extirpation defects that are not amendable to local tissue closure. In such cases, the free tissue transfer was a useful alternative because it can provide large amount of well-vascularized tissues and reliable separation of intracranial space from bacterial flora of the upper airway. The microvascular free tissue transfer was used in 9 patients at our center to reconstruct the cranial base defects. Of these, 8 were free rectus muscle flaps, and 1 was free latissimua dorsi muscle flap. There were 1 case of partial flap loss and 1 case of postoperative wound infection. The large, complex defects were successfully reconstructed by one stage operation and the functional and aesthetic results were satisfactory with acceptable complication rates.