Introduction. Periodic legs movements of sleep (PLMS) are rhythmic, standard and repetitive contractions of muscles of the extremities during the sleep. It is known that the patients with restless legs syndrome (RLS) have disorders during the sleep: increase in the latency of the sleep, increased number of arousal, etc.; most of them have also periodic movements of the legs during the sleep. Objective. The relationship of the periodic movements of the legs during the sleep with polyneuropathy is not clear. Some authors have found evidence of electrophysiological and pathological of signs of axonal mild polyneuropathy in patients with restless legs syndrome. In this work, we evaluated nine patients that were diagnosed of PLMS, to determine the prevalence of neuropathy in such sample. Method. Polysomnography of nocturnal sleep of 7-8 hours was performed, including electromyographic recording of both anterior tibialis muscles; and electroneurographic study of peroneal, sural, ulnar and median nerves. Discussion. Just in none of the nine studied cases were obtained electrophysiological signs of neuropathy; though it has been able to demonstrate the existence of mild alteration of the peripheral nervous system, fundamentally of sensory character; nevertheless,C we think that it would have to be studied the existence of polyneuropathy in all the patients with PLMS in order to discard potentially tractable organic causes