Two cases of primary antiphospholipid antibody syndrome are reported. One patient presented multiple abortions and epilepsy. The second patient was affected by a brain vascular accident, with a residual hemiparesis. Both cases showed livedo reticularis in arms, NMR evidence of diffuse lesions of the white matter, high serum levels of anticardiolipin antibodies and cardiopathy. Lupus anticoagulant was also found in the serum of the first patient, and cortisone and antiaggregants enabled her to reach term in a fifth pregnancy after four miscarriages. In the other case histological examination of specimens of skin, peripheral nerve and skeletal muscle revealed occlusive, non arteriosclerotic vasculopathy and an absence of inflammatory lesions. Histological study has rarely been performed in primary antiphospholipid syndrome but suggests that the mechanism of thrombosis is not vascular; in our subjects it revealed findings similar to those in Sneddon syndrome.