Neurological or psychiatric symptoms are present in 60% of the cases with systemic lupus erythematosus. Direct lesions of nervous system are associated with the presence of antibodies, vasculitis, thrombosis and impairments mediated by cytokines. Damages caused by injuries of other organs or those due to therapy are known as indirect causes. In the complex pathogenesis the primary cause is neuronal dysfunction mediated by autoantibodies, vasculopathia and coagulopathia. Until now, more than 20 antibodies have been identified in association with damages of the nervous system. These antibodies may impair neurons or astrocytes and may promote thrombotic processes in vessels of the brain. Activation of endothelial cells and disturbance of blood-brain barrier are also pathogenic factors. In patients with systemic lupus erythematosus the most frequent psychiatric manifestations are organic psychosyndrome, particularly deterioration of cognitive functions, and depression, while the most common neurological syndromes are epilepsy and ischemic stroke. In the pathogenesis of antiphospholipid syndrome β2-glycoprotein I plays the most important role; binding to its antibody the complex may interact with cells and modify haemostatic actions. The most frequent neurological manifestations of antiphospholipid syndrome are headache and ischemic stroke.