Idiopathic intracranial hypertension, or Pseudotumor cerebri is a disorder characterized by symptoms and signs of a space-occupying intracranial mass without any evidence of mass or ventricular obstruction. We experienced a 28 years old obese woman who was presented with headache and progressive visual disturbance for one month. She presented bilateral papilledema with visual field defect. On MRI investigation no intracranial abnomality were observed. Lumbar puncture showed increased intracranial pressure and normal biochemical and cellular findings. The patient was diagnosed idiopathic intracranial hypertension and treated with therapeutic lumbar puncture, acetazolamide, furosemide, weight control and symptoms resolved gradually. We conclude that weight reduction is difficult to accomplish but always needed in idiopathic intracranial hypertension. (J Korean Acad Fam Med 2007;28:626-630)