Chronic lead encephalopathy must be considered in the differential diagnosis of pediatric patients who present with manifestations of schizophrenia, behavior disorders or degenerative diseases of the central nervous system. Determination of urinary coproporphyrin is a simple, fast screening procedure applicable to office practice. The prognosis for normal mental development following encephalopathy is poor. It is hoped that early recognition of the more subtle signs of central nervous system involvement will allow treatment to be instituted soon enough to prevent the crippling mental deterioration which is so often a sequela of lead poisoning.