Thirty one healthy people and 49 patients suffering from diseases of the nervous system were studied in order to evaluate the technique of eliciting Babinski's signal by means of cold stimulation as it was proposed by Dalsgaard-Nielsen. The patients were distributed in 4 groups. Patients of group 1 (7 cases) had clinical signs of peripheric nervous system impairment. Patients of groups 2, 3 and 4 had clinical signs of CNS impairment. In those of group 2 (12 cases) there were no evidences of central motor lesions. In the remaining patients these evidences were found and they were grouped considering the absence (group 3: 9 cases) or the presence (group 4: 21 cases) of Babinski's sign, when tactile stimulation was used. The results obtained were compared to those found in the same people by means of tactile plantar stimulation. For both methods, results were considered to be: absent, when any motor reflex activity was elicited; in-characteristic, when it was observed a rapid dorsiflexion of toes; normal, when the ventral flexion of toes proper to cutaneo-plantar reflex occurred and Babinski's sign, when it occurred the hallux dorsiflexion proper to this signal. The results obtained show that the plantar cold stimulation is not useful for eliciting the normal cutaneo-plantar reflex. It was elicited by this method only in 2 healthy people and in 3 patients of groups 1 and 2. Babinski's toe phenomenon was elicited by cold stimulation in 18 patients of group 4. It was observed that the response was more characteristic and remained by a longer period when cold stimulation was used. These aspects were observed specially in those patients that had bilateral Babinski's sign. The results show that cold stimulation of the plantar region is an useful method of eliciting Babinski's toe phenomenon. The qualitative aspects of the motor response which were refered show that cold stimulation is an useful method of investigation to be employed specially when doubtful responses are obtained by tactile stimulation techniques.