The authors report on 2 young patients who developed drug-resistant idiopathic dystonic camptocormia (bent spine) and were treated successfully by deep brain stimulation (DBS) of the globus pallidus internus (GPi). The first patient, a 26-year-old woman, suffered for 3 years from such severe camptocormia that she became unable to walk and was confined to bed or a wheelchair. The second patient, a 21-year-old man, suffered for 6 months from less severe camptocormia; he was able to walk but only for short distances with a very bent spine, the arms in a parallel position to the legs, and the hands almost approaching the floor to potentially support him in case of a forward fall. Within a few days following DBS, both patients experienced marked clinical improvement. At most recent follow-up (44 months in one case and 42 in the other), the patients' ability to walk upright remained normal. Similar findings have only been reported recently in a few cases of camptocormia secondary to Parkinson disease or tardive dyskinesia. On the basis of the experience of these 2 idiopathic cases and the previously reported cases of secondary camptocormia with a favorable response to GPi DBS, the authors postulate that specific patterns of oscillatory activity in the GPi are vital for the maintenance of erect posture and the adoption of bipedal walking by humans.