Deep vein thrombosis and pulmonary embolism can be considered as one clinical entity, termed venous thromboembolism, because of their comparable pathogenesis, treatment and prognosis. In this clinical spectrum of venous thromboembolism a gradient in severity of the disease can be recognized. Therapeutic strategies should be adapted to the extent of the thrombotic disease, varying from surgical or thrombolytic therapy in life-threatening disease to a watchful waiting diagnostic follow-up approach in minimal disease. In patients with established venous thromboembolism (low molecular weight) (LMWH), heparin should be initiated. An overview will be given of the safety and efficacy of the different therapeutic modalities such as thrombectomy, thrombolytic therapy, a watchful waiting diagnostic approach and unfractionated heparin. Furthermore, clinical studies comparing LMWH with unfractionated heparin in the initial treatment of venous thromboembolism will be reviewed.