We report a patient with a meningioma presenting with Cushing's syndrome, an unprecedented paraneoplastic presentation. Molecular studies, bioassay, and high-performance liquid chromatography of tumor specimens demonstrated the synthesis and secretion of bioactive corticotropin-releasing hormone. To our knowledge, this appears to be the first report of a hormone-secreting meningioma and, further, the first clearly proven case of Cushing's syndrome due to ectopic corticotropin-releasing hormone secretion without concomitant corticotropin production.