Hemicraniectomy and opening underlying dura mater permits the expansion of infarcted, swollen brain outwards, reversing dangerous intracranial pressure elevations and the risk of fatal transtentorial temporal lobe or diencephalic herniation. Recently published randomized controlled trials have proven this procedure a powerful life-saving measure in the setting of malignant middle cerebral artery infarction and allayed concerns that a reduction in mortality is accompanied by an unacceptable increase in patients suffering severe neurological impairments. Appropriate patients are relatively young, in the first five decades of life, suffering infarction of a majority of the middle cerebral artery (MCA) territory in either hemisphere, and decompression should be performed prior to progression to coma or two dilated, fixed pupils. Lethargy combined with midline shift and uncal herniation on neuroimaging is an appropriate trigger to consider and discuss surgical intervention. Families and, when possible, patients themselves, should be informed of the certainty of at least moderate to mild permanent deficits, and the possibility of worse. To be successful decompression must be extensive, targeting a bone flap measuring 14 cm from front to back, and extending 1 to 2 cms lateral to the midline sagittal suture to the floor of the middle cranial fossa at the level of the coronal suture. An augmentation duraplasty is mandatory.