The Authors submitted 53 randomly selected patients affected by systemic lupus erythematosus (SLE) to neurologic evaluation to investigate the prevalence of neurologic manifestations, establish relationships to clinical and epidemiological findings and antinuclear antibodies and/or lupus anticoagulant (LAC), as well as to assess the usefulness of electroencephalogram (EEG), saccadic eye movements (SEM) analysis, brain computerized tomography (CT). Twenty-two patients (41.5%) had nervous system involvement on anamnestic and/or clinical examination: there were seizures in 5 patients, headache in 3, involuntary movements in 3, psychosis in 2 and cerebrovascular disorders in 9. The patients were subdivided into 2 groups, with neuro-SLE and without neuro-SLE, according to clinical and/or anamnestic evidence of nervous system involvement. There were no differences between the two groups of patients regarding disease duration, disease activity, presence of antinuclear antibodies and/or LAC. EEG and/or SEM and/or brain CT abnormalities were found in 38 cases, 18 of which had no clinical evidence of neuro-SLE. Instrumental evaluation can thus document subtle nervous dysfunction and offers the possibility of classification into: a) non-neuro-SLE; b) subclinical neuro-SLE; c) overt neuro-SLE.