Objective: To characterize the obesity phenotype(s) in patients with idiopathic intracranial hypertension (IIH). Design: Database study. Participants: We studied 44 consecutive patients with IIH, in addition to 184 women attending the obesity clinic of the same medical center and 199 obese women participating in the first Israeli national survey on health and nutrition conducted in 1999 and 2000. Methods: Anthropometric parameters were compared with those of 2 control groups of the same age range. Main Outcome Measures: Weight, height, and waist and hip circumference were measured. Results: Forty subjects, comprising 91.0% of this cohort, were either overweight (body mass index, 25.0-29.9 kg/m2) or obese (body mass index ≥ 30 kg/m2). Mean waist circumference was 95.3 cm for IIH, 99.8 cm for the national survey, and 114.5 cm for the obesity clinic cohort (P<0.001), whereas hip circumference was 121 cm for IIH, 118.4 cm for the national survey, and 125.8 cm (P = not significant) for the obesity clinic cohorts. Waist-to-hip ratio, a descriptive measure of body fat distribution approximately reflecting upper to lower body fat ratio, was 0.79 in the patients with IIH, 0.84 in the national survey group, and 0.91 in the obesity clinic cohort (P<0.001; all comparisons were adjusted for age and body mass index). Conclusions: In IIH, fat tends to preferentially accumulate in the lower body relative to other obese women of the same range. Whereas most complications of obesity, such as hypertension, diabetes, dyslipidemia, and the metabolic syndrome, are linked to upper body adiposity, IIH may represent a unique condition potentially induced by nonvisceral fat-related mechanisms. Financial Disclosure(s): The authors have no proprietary or commercial interest in any materials discussed in this article.