By the neurological, electromyographic, anatomopathological and bacterioscopic examinations of 100 pacients with leprosy the following conclusions have been drawn: There was a high incidence of reflex abnormalities. The proprioceptive reflexes were abnormal in 64.5% and the superficial reflexes in 70.8% of the cases. According to the topography of the segments examined, the deep reflexes showed the following abnormal values: 25.3% in the cephalic segment; 69.1% in the upper limbs and 74.5% in the lower limbs. Of the 2,289 reflexes investigated, abnormalities were found in 773 superficial reflexes (70.8%), while in relation to the proprioceptive reflexes the figures rose to 901 (64.5%). In the early stages of the infirmity, the reflexes were normal in 41.2% of the cases examined, and in all the stages of the evolution of the disease those numbers were always high. Also in the first stage, whose average duration was of 4.9 years, several alternations were noted, although there was a predominance of brisk reflexes (25.1%) over diminished reflexes (17%), followed by hyperactive (8.6%) and absent reflexes (8%). In the final stage of the infirmity there was a decrease of normal reflexes, in contrast to absent and decreased reflexes, whose rates increased to 32.7% and 30.6% respectively. The disappearance of hyperactive reflexes and the clear decrease of brisk reflexes should also be noted. There was a high percentage of patients (31%) who suffered agression of the eighth nerve, 17 of which (54.8%) were found to suffer from neural deafness. The values related to hearing deficit were rarely in accordance with the histopathological and bacterioscopic positive results. The indexes of abnormalities found out in the examination of the fifth and of the seven nerve (7% and 5% respectively) were much lower in relation to the eighth nerve. These results are in contradiction with the ones stated in the literature. In some of the patients, hyperesthesia of the skin of the plantar region prognosticated the appearance of the infirmity. Among the objective changes, anesthesia of superficial sensibilities combined with deep hyperesthesia and anesthesia of superficial sensibilities with abolition of profound sensibilities were rarely observed. No case was found with exclusive alterations of deep sensibilities. Peripheral motor neuron lesions demonstrable by electromyography were observed in 82 patients (82%). The electric silence and the giant polyphasic potentials were the most frequently noted abnormalities. In a small number of cases pseudomyotonic alterations were registered. Among the patients with indicative signs of recent denervation, 50% presented negative bacterioscopic results. There was predominance of electromyographic abnormalities in the virchowian forms. In relation to the nerves investigated, there was greater injury of the ulnar, by comparision with the median and the deep peroneal nerves. The study of the average speed of conduction of motor fibers in the median, ulnar, and deep peroneal nerves gave the following results: 53.6; 48.1 and 50.3 meters per second, respectively. The averages of the distal and proximal latencies of the median nerve were 3.8 and 8.4 m/seg; in the ulnar nerve, 3.0 and 9.2 m/seg; in the deep peroneal nerve, 4.4 and 11.6 m/seg.