Selective dorsal rhizotomy at the lumbar level is a neurosurgical procedure, which reduces spasticity in the legs. Its effect has mainly been studied in children with spastic cerebral palsy. Little is known about the outcome of selective dorsal rhizotomy in patients with neurodegenerative disorders. We report the clinical course after selective dorsal rhizotomy in 2 patients with progressive spasticity. Leg spasticity was effectively and persistently reduced in both patients, facilitating care and improving sitting comfort. However, spasticity of the arms and other motor disturbances, such as spontaneous extension spasms and the ataxia, increased gradually in time. Selective dorsal rhizotomy leads to a disappearance of leg spasticity in patients with a neurodegenerative disease. Other motor signs are not influenced and may increase due to the progressive nature of the underlying disease. © 2008 Sage Publications.