Experiences in the surgical treatment of spastic syndromes by operations on the human spinal cord and nerve roots are reported. Twenty lumbar myelotomies, 19 posterior selective lumbar rhizotomies, 2 complete posterior lumbar rhizotomies, 4 anterior lumbar rhizotomies and 5 posterior cervical rhizotomies were performed. Clinical results can be considered good on the whole. There was no mortality and no major complication in the entire series. The effect of selective posterior lumbar rhizotomy on the evolution of cerebropathic spastic paraparesis was particularly impressive. Of 46 patients, 6 experienced a late recurrence of spasticity, but they all had good results after a further operation. The particular criteria for selection of each surgical procedure are discussed and related to the etiology and clinical picture of the spastic syndrome.