Idiopathic intracranial hypertension (IIH) is the syndrome of raised intracranial pressure (ICP) without clinical, laboratory or radiological evidence of intracranial pathology. IIH is a relatively rare disease but rapidly increasing incidence is reported due to a global increasing incidence of obesity. Disease course is generally said to be self-limiting within a few months. However, some patients experience a disabling condition of chronic severe headache and visual disturbances for years that limit their capacity to work. Permanent visual defects are serious and not infrequent complications. The pathophysiology of IIH is not fully understood yet. Advances in neuroimaging techniques have facilitated the exclusion of associated conditions that may mimic IIH. No causal treatment is yet known for IIH, and existing treatment is symptomatic and rarely sufficient. The aim of this review is to provide an updated overview of this potentially disabling disease. Theories of pathogenesis, diagnostic criteria and treatment strategies are discussed.