Antiphospholipid Syndrome (APS) is an immune thrombophylia of unknown etiology which leads to vascular thrombosis and gestational complications.A 27-year old woman who had been diagnosed APS four years before was admitted in the Emergency Room five days after a spontaneous delivery due to [corrected] pain in the upper right abdominal quadrant. Blood analysis revealed AST and ALT rise and thrombocytopenia. CT scan was suggestive of liver infarction due to venous ischemia. Abdominal eco-doppler diagnosed vena porta left branch thrombosis and compensatory arterial circulation. Treatment included low molecular weight heparin and corticosteroids which led to progressive clinical, laboratory and imagiological recovery.Portal venous system thrombosis is extremely rare in the absence of local risk factors and the most common and catastrophic complication is intestinal necrosis.