Large Intracerebral hematoma (ICH), compounded by perihematomal edema can produce severe elevations of intracranial pressure (ICP). Decompressive craniectomy (DC) beneficially addresses mass effect. Therefore this study is aimed to prove that decompressive craniectomy with durotomy has better outcome in patients with spontaneous supratentorial ICH than conservatively treated patients. This Quasi-Experimental study was carried out in the Department of Neurosurgery, Dhaka Medical College & Hospital (DMCH), Dhaka, Bangladesh from July 2012 to December 2013 using purposive sampling procedure. A total of 80 admitted adult hypertensive patients with spontaneous supratentorial ICH were enrolled in the study population fulfilling all selection criteria. Of them 40 patients underwent decompressive craniectomy with durotomy was considered as surgical group and 40 patients were treated conservatively was considered as conservative group. All the cases were continuously followed up and GCS score at 7(th) day of treatment (D7) and at discharge was recorded. Mean±SD hematoma volume was 56.91±13.72ml in surgical patients and in conservative group 51.80±13.58ml. Outcome measured by modified Rankin Scale at 3 months. Sixty percent (60%) patients had good outcome (mRS 0-4) and 40% patients had poor outcome (mRS 5-6) in surgical group. On the other hand, 52.5% patients had good (mRS 0-4) and 47.5% had poor (mRS 5-6) outcome in conservative group. In logistic regression analysis, conservative group was 3.643 times more prone to develop poor outcome than surgical group which was statistically significant (95% CI, 1.040-13.047; p value <0.05) and volume of hematoma [OR (95% CI), 1.131(1.059-1.207); p value <0.001)] was the most important predictor of outcome. This study indicates that decompressive craniectomy with preservation of brain integrity in patients with spontaneous supratentorial ICH is feasible and safe. It can be a useful alternative surgical procedure in the treatment of spontaneous supratentorial ICH.