An 18-year-old woman with Gitelman syndrome (GS) associated with idiopathic intracranial hypertension (IIH) is described. She was obese and showed a 10 kg gain in body weight over a period of 8 months. She presented with headache, vomiting, and diplopia. She had bilateral papilledema, and right abducens palsy. CSF examination demonstrated high pressure (over 320 mmH(2)O) with normal cytochemistry. Brain MRI was normal. She showed mild alkalosis, hypokalemia, hypomagnesemia, increased plasma renin activity, and normal blood pressure. Two heterozygous mutations in the SLC12A3 gene were identified. Therefore, she was diagnosed as GS with IIH. We should keep in mind the possible occurrence of IIH in GS.