Elastic compression (EC) is highly recommended in prophylaxis and treatment of venous disorder of the human leg. However, the exact mechanisms of its action are not enough understood and the response of internal tissues to the external pressure are still partially unknown. A 3D biomechanical FE model for simulating the effect of EC on the human leg has been developed based on the actual geometry of a female leg, obtained from 3D CT-scan images. The model is made up of soft tissues (fat and muscles) and rigid bones. A 2D FE model, reconstructed from MRI, is used to identify the elastic properties of soft tissues by an inverse method. The pressure applied by EC increases linearly from ankle to knee. The results show a non homogeneous pressure field (more than 35 % of discrepancies in a cross section of the leg) bringing evidence that the socks should be adapted to the diseased vein location.