Although the co-occurrence of cerebellar ataxia and hypogonadism has been recognized for close to 100 yr, cases of Gordon Holmes syndrome are quite rare. This report describes the largest kindred characterized to date. The parents of the three affected siblings are first cousins, suggesting that the disease was inherited as an autosomal recessive trait. The siblings’ initial evaluation was notable for low serum levels of sex steroids and gonadotropins (consistent with hypogonadotropic hypogonadism), progressive ataxia, and dementia. Extended treatment with physiological doses of pulsatile GnRH failed to stimulate a gonadotropin response. Brain imaging revealed volume loss in the cerebellum, with extensive abnormalities in the cerebral white matter. This unique family suggests that a common genetic mechanism is responsible for the syndrome of progressive hypogonadotropism and cerebellar ataxia.