Objective: Malignant middle ceerebral artery (MCA) infarction is characterized by mortality rate of up to 80% because of increasing brain swelling, raised intracranial pressure (ICP), and brain herniation. The aim of this study was to determine the value of decompressive surgery outcome in patients who present large MCA territory infarction. Methods: From January 2001 to October 2005, We underwent 24 cases of decompressive surgery (6 cases craniectomy with duroplasty, 8 cases of craniectomy with lobectomy and duroplasty, 10 cases of caraniotomy with wide resection of the infarction area) in the management of malignant  MCA territory infacrctions. Initial clinical presentation was accessed by th Glasgow Outcome Scale (GOS) and the modified Bartel Index (BI) at 6 months after surgical decompression. The volume of the infarction area and the midline shift were estimated in PACS system (PiView STAR®, Infinitt Co. Korea) before and after the surgery.  Results: The patient ages ranged from 39 to 71 years (mean, 58 years) and included 11 males and 13 females The mortality was 16.7% and th mean GOS and the BI was 3, 52.6, respectively. The reductions of the midline shift, in decreasing order of degree, were craniotomy with wied reseciton of the infarction area (strokectomy), craniectomy with lobectomy and duroplasty, craniectomy with duropasty. But, were no significant differences in functional outcome by the surgery type and age group (<65, ≥65). The patients who had an infarction volume below 240 cm³ had better funcional outcome with mean BI of 68 than the patients more than 240 cm³ with mean BI of 44.4  Conclusion: With these results,  decompressive surgery seems to play a crucial role for life saving in the patients with malignant cerebral infarction, and showed favorable functional outcome, even in elderly patients. Although there was no significant difference in functional outcome by the surgery type, osteoplastic craniotomy with wide resection of the infarction area has the advantage of early reduciton of intracranial pressure and prevent from secondary cranioplasty, especially in eldery patients or patients with heart problem.