Sneddon syndrome is characterized by livedo reticularis and multiple cerebral infarctions. Skin and central nervous system symptoms usually have a synchronous onset and at times initial symptoms affect one of them, the other lagging several years behind. We here report a patient with Sneddon syndrome who developed multiple cerebral infarctions more than 10 years after the onset of livedo reticularis. While the neurological symptoms were apparent, the patient did not display active skin manifestations. Laboratory findings excluded collagen diseases, antiphospholipid antibody syndrome, and inherited quantitative deficiency of protein C, protein S and antithrombin III. Abnormal findings included extremely elevated levels of beta-thromboglobulin and platelet factor-4 in the blood, although these acute phase markers of thrombosis were examined several years after the onset of cerebral infarctions. Platelet activation may have caused Sneddon syndrome in the present case.