Cerebral palsy is the most common motor disorder originating in childhood and spasticity is the most frequent manifestation. The treatment strategies to reduce spasticity and thereby ameliorate the attendant gait abnormalities have included physiotherapy, orthoses, antispastic medications, orthopaedic surgery and neurosurgery. Of these, the neurosurgical procedure known as selective dorsal rhizotomy has gained widespread exposure, and indeed acceptance, over the past two decades, despite there being some controversy as to its efficacy. In this paper we review: cerebral palsy, including classification and treatment; selective dorsal rhizotomy, including historical background, patient selection, operative procedure, clinical outcome and complications; and gait analysis studies, including temporal-distance parameters, joint kinematics, normalisation for growth, and long-term follow-up. Both the short-term (1 year) and long-term (10 years) evidence has demonstrated that selective dorsal rhizotomy not only reduces spasticity but it also provides lasting functional benefits as measured by improved range of motion during gait. Rhizotomy is not a panacea for children with spastic diplegia but it is an important treatment option for the clinician to consider. Copyright 1998 Elsevier Science B.V.