Eleven patients with chronic lead intoxication were submitted to somatosensory evoked potential (SEP) studies. All patients demonstrated increased lead blood levels and reduced ALA D activity in red blood cells. Three patients showed delayed spinal arrival (N13 wave), four delayed cortical arrival (N20 wave), and three prolonged central conduction time (time elapsing between N13 and N20 waves) (see table 1). No relationship was found between the abnormal findings and the levels of lead or ALA D. Time of intoxication was not related to the altered electrophysiological features either. The findings reported suggest that, beside the well known peripheral involvement in chronic lead intoxication, some patients may develop central nervous system impairment perhaps related to myelin involvement as suggested by the prolonged SEP central conduction time.