This chapter provides detail description of Vasospasm and its management. Chapter has 6 well illustrated diagrams and pictures. Vasospasm, historical overview of vasospasm, chronology, risk factors for developing vasospasm, site of occurrence of vasospasm, classification and grading of vasospasm, experimental models for studying vasospasm, aetiopathogenesis of vasospasm, biology of cerebral blood vessels, genetics and pathophysiology of vasospasm at molecular level, red blood cells components and other spasmogens, vasculopathy, trauma of manipulation of arteries, hypothalamus, sympathetic plexus, apoptosis and vasospasm, cascade of events before and after vasospasm, early brain injury, clinical features of vasospasm, investigation related to vasospasm, cerebral blood flow studies, electroencephalography, transcranial Doppler, computerized tomography-angiography, single photon emission computed tomography, treatment of vasospasm, triple-H therapy, pharmacological prevention of vasospasm, free radical scavengers, recombinant tissue plasminogen activator, timing of surgery in relation to vasospasm, cerebrospinal fluid drainage, outcome of patients with vasospasm are described in detail. 305 references are included at the end of the chapter to facilitate further reading.