Summated responses to peroneal nerve stimulation were recorded from surface electrodes placed over the spine of 60 infants and children. These potentials generally were greater in amplitude in infants than in older children. Over the cauda equina and rostral cord, initially positive triphasic potentials were recorded. Over the caudal cord, complex potentials were recorded in children less than three years of age. The conduction velocity of the response from midlumbar to lower cervical recording sites was less in infants than in older children and progressively increased with age, reaching adult values after the fourth year.