The antiphospholipid syndrome (APS) is defined by the association of high titers of antiphospholipid antibodies (aPLs) with thrombotic events and/or obstetrical problems. APS can be isolated or associated with immune system diseases. Several central nervous system (CNS) manifestations have been reported in APS, but are still not included in the international diagnostic criteria. We present here three cases of APS revealed by CNS manifestations. The first patient had a primary APS with stroke, dementia, epilepsy and the "so-called" Liebman-Sacks disease, a subacute thrombotic non-bacterial valvulopathy. The second one developed a primary APS with a Sneddon syndrome, while the third case is a neurolupus-associated APS with subacute encephalopathy, chorea, stroke, and epilepsy. The pathogenesis of the APS is related to both prothrombotic and immunologic effects of the aPLs. Long-term anticoagulation by low-weight heparin or warfarin is currently recommended in APS. We propose to search the presence of aPLs in any case of young adults' stroke, unexplained dementia, and acquired chorea.