Essential thrombocythaemia is a chronic myeloproliferative disorder characterized by the proliferation of megakaryocytes in the bone marrow, leading to a persistent increase in circulating platelets. Apart from this increase (>600 x 10(9)/L) this disease also exhibits accentuated hyperplasia of the megakaryocytes in the bone marrow, splenomegaly and clinically both thrombotic and haemorrhagic episodes. The etiology of this illness is largely unknown and the clinical manifestations are mostly asymptomatic, thus the diagnostic is often accidentally made. Here the case report of a 71-year-old male patient is discussed, who was admitted into hospital due to occlusion of the femoral artery requiring re-vascularisation. The physical exam showed that the patient suffered several other symptoms related to essential thrombocythaemia. In conclusion, this is a grave, potentially fatal disease which needs further study to determine the etiology. Early diagnosis and treatment are crucial for a good prognosis.