The neurointensive care unit provides observation and treatment of acute, life-threatening disorders of and injuries to the central and peripheral nervous system. The primary aim of care is the prevention of secondary neuronal damage; this requires a highly multidisciplinary approach, involving neuromonitoring as well as management of systemic comorbidity and complications. This article presents major pathophysiological issues specific to neurointensive care, as well as recent advances in the management of the critically-ill neurosurgical and neurological patient.