During the acute phase of the disease the aim of conservative treatment of DVT is relief of symptoms as well as prevention of thrombus progression and pulmonary embolism. In the chronic phase treatment should prevent recurrence and post-thrombotic syndrome. Besides general measures such as compression therapy, elevation of the leg and mobilisation anticoagulation therapy with heparin and coumarin has been proved to be successful. Even though not more effective or safer low-molecular weight heparin has recently replaced unfractionated heparin in the initial treatment of DVT mainly because of its more convenient use allowing modern ambulatory and outdoor treatment. Doses depend on the kind of heparin used. In the secondary prevention therapy with coumarins, an INR of 2-3 is generally accepted whereas the duration of oral anticoagulant therapy is under discussion. Compression therapy is recommended for at least 2 years, in case of post-thrombotic syndrome life-long therapy is necessary. When comparing the effectiveness of DVT-treatment today with the results in the preanticoagulant era, the modern treatment is more effective, safe and cost-effective; it also guarantees more quality of life, but the long-term results have to be improved.