The presence of anti-phospholipid antibodies (anticardiolipin antibodies and lupus anticoagulant) associated to venous and/or arterial thrombotic phenomena and fetal losses define the anti-phospholipid syndrome. On rare occasions severe hypoprothrombinemia associated with this disease as a cause of hemorrhagic manifestations has been described. In addition very few cases of alveolar hemorrhage in anti-phospolipid syndrome (APS) have been described, being this complication usually related to microthrombosis and/or capillaritis of pulmonary vessels. We describe two patients without previous clinical manifestations of anti-phospholipid syndrome that showed pulmonary hemorrhage with anticardiolipin antibodies positivity. The first of them, a 33-year-old male, began his disease with low prothrombin time and the presence of antiprothrombin antibodies. In the biopsy by thoracoscopy the presence of pulmonary hemorrhage without capillaritis nor thrombotic phenomena was demonstrated, becoming evident certain clinical improvement and normalization of the prothrombin time after receiving immunosuppressive treatment but with persistence of the pulmonary hemorrhage 5 years later. The second case, a 89-year-old male, began his condition with bilateral lung infiltrates and hemoptysis, anticardiolipin antibodies positivity, and thrombopenia, with recurrence of the condition 1 year later. After other etiological possibilities were ruled out, and despite hemorrhagic trait in both patients, we consider that they should be in the clinical context of the anti-phospholipid syndrome, although at this time they did not meet the criteria recognized in order to diagnose this disease. Within the ampliable clinical spectrum of the anti-phospholipid syndrome we should take into account the pulmonary hemorrhage.