Background: Malignant Middle cerebral artery territory (MCA) infarction constitutes about 10% of ischemic strokes. Though Decompressive Hemicraniectomy (DHC) has shown decreased mortality, the functional outcome and prognostic markers are still inconclusive. Objective: To determine the prognostic markers and functional outcome of Decompressive Hemicraniectomy in a series of patients with Malignant MCA Infarction. Methods: This was a prospective study from November 2015 to December 2017 at tertiary care hospital. Totally, 52 patients with massive MCA infarct were included in this study. All the patients were analysed elaborately both in pre-operative and post-operative period. The functional outcome was assessed with Barthel index (BI) during the follow up period of 6 months. Results: Out of 52 patients, 23 patients (44.2%) had favourable outcome (BI > 60). The good prognostic factors noted were age less than 45 years (60.9%), surgery done within 24 hours (73.3%), right sided infarction (60.9%). Early return of consciousness within 5 days in post-operative period and absence of clinical signs of herniation pre-operatively had statistically significant functional outcome based on BI>60 over 6 months follow up. Mortality was noted in 23.1% of patients. Conclusion: Decompressive hemicraniectomy is a favourable surgical treatment in patients with massive middle cerebral artery infarction. Age less than 45 years, right sided infarction, surgery done within 24 hours from ictus especially before clinical signs of herniation and postoperative regaining of consciousness within 5 days after surgery are good prognostic markers.