We performed neuropsychological tests to investigate higher cortical dysfunction in 21 patients with systemic lupus erythematosus (SLE). We also measured antiphospholipid antibodies (APA), performed brain computed tomography (CT), and obtained a single photon emission CT (SPECT) to measure regional cerebral blood flow (rCBF) in order to elucidate a possible relationship between APA and higher cortical dysfunction. Higher cortical dysfunction was noted in as many as 16 (76%) out of 21 cases. APA were positive in 8 (38%) out of 21 cases. Although the relationship between APA and higher cortical dysfunction was not significant, patients positive for lupus anticoagulant (LA) were found to have higher cortical dysfunction. Brain CT revealed at least one abnormality in 6 cases (29%) but none had a localized lesion, SPECT disclosed a reduced rCBF in 9 cases (43%). The findings on brain CT and SPECT were unrelated to higher cortical dysfunction.