Severely ill neurosurgical patients are those who present with pathologies of the nervous system associated with either a high mortality or that which leaves significant sequelae in those who survive. Desmopressin is a synthetic analog of the antidiuretic hormone that is stored in neurohypophysis. Its function is to decrease urinary volume by increasing reabsorption of water in the convoluted tubules and nephron collectors, additionally increasing the expression of coagulation factor VII and the von Willebrand factor. For this reason, its usefulness in the management of various pathologies has been tested, from coagulopathies to posttraumatic and postsurgical diabetes insipidus. It contributes in improving hyponatremia and in maintaining the balance of fluids and electrolytes in traumatic brain injury and subarachnoid hemorrhage (SAH) patients. It has been additionally studied for its role in the risk of rebleeding in SAH patients and in those with coagulopathies, where its implicated mechanism of action is through platelet anti-aggregation.