Cerebellar stimulators were inserted into seven children who had cerebral palsy and in whom extensive investigation. including computerized tomography, had revealed no structural brain abnormality. A team including physiotherapists, occupational therapists, speech pathologists, and respiratory physiologists assessed the children pre- and postoperatively; their somatosensory evoked potentials were also measured. The mean age at implantation was 8.6 years; follow-up has ranged from 8 to 23 months (mean, 17.3 months). No adverse effects of the cerebellar stimulation have been noted. Detailed case histories obtained from the parents, together with formal assessment scores, indicate good improvement in six patients and mild but significant improvement in the seventh. Clinically, there has been gradual improvement in all seven patients. The charge density range associated with clinical improvement was 0.8 to 2.1 μCi/cm2/phase. The stimulation equipment must be monitored very carefully to ensure that any variation from the desired output is acceptably small because it is probable that sizable deviation is a determining factor in lack of response to this therapy.