Painful ophthalmoplegia due to idiopathic granulomatous inflammation of the cavernous sinus/superior orbital fissure has been termed Tolosa-Hunt syndrome (THS). This report is based upon 146 patients with this syndrome published in the English literature. The clinical profile, natural history, diagnostic evaluation, pathologic findings, differential diagnosis, and therapy of THS are presented. Careful initial patient examination and scrupulous follow-up evaluation are essential, as THS is categorically a diagnosis of exclusion. While the etiology of THS is unknown, current pathogenetic theories are reviewed.