Central nervous system involvement in systemic lupus erythematosus is rather frequent whereas peripheral nervous system involvement is much less common. The three patients studied by us had isolated manifestations uncommon in nature. The first one developed a sensory-motor polineuropathy with signs of axonal degeneration. It responded to the therapeutic association of corticosteroids with an immunosuppressive agent. Satisfactory recovery took place over a time span of a year. The second patient had encephalic and cerebral trunk involvement from which an irreversible dementia resulted. The third patient, who had recurrent aseptic meningitis, is asymptomatic for six months now. Patients one and two had no systemic manifestations at the time of nervous system involvement. Suspicion of systemic lupus erythematosus was made on the basis of past inspecific articular symptoms. The neurological and systemic manifestations may be sometimes simultaneous; they are usually followed by serologic changes. Isolated nervous system involvement may be seen with and without sorologic changes, and there may be found antibodies reactive with phospholipids (anticardiolipin, antigangliosides and anticerebrosides). The employment of nonsteroid immunosuppressive drugs associated with corticosteroids in small doses seems to be useful in cases of systemic lupus erythematosus with nervous system involvement.