In a prospective study of 24 consecutive patients satisfying all clinical, cerebrospinal fluid and CT scan criteria for benign intracranial hypertension (BIH), angiography showed cerebral venous thrombosis affecting dural sinuses (CSVT) in 6 (25 ± 17%, 95%, confidence limits). When comparing patients with (n = 6) and without CSVT (n = 18), the only statistically significant difference concerned the prevalence of obesity (CSVT = 1/6; BIH = 14/18, p < 0.03). Another trend emerged but did not quite reach statistical significance (sex ratio female/male: CSVT = 3/3; BIH = 17/1, p < 0.07). The present study shows that CSVT can present with all the clinical and radiological criteria of BIH and illustrates the need for angiography or MRI to rule out this possibility, particularly in males and in nonobese females