Strain imaging is useful for visualizing information related to tissue stiffness. However, strain is a parameter that depends on the boundary conditions, tissue connectivity and geometry. As a result, tissue hardness cannot be quantitatively evaluated from the strain distribution. Therefore, reconstruction of the elastic modulus (Young's Modulus) distribution has been investigated for quantitative evaluation of tissue hardness. A method has been recently proposed [NITT 00] to calculate locally the Young's modulus of tissues from the estimations of 3D displacement field within the medium. This approach requires a specific annular ultrasonic probe. The aim of our work, based on Nitta's approach, is to build a Young modulus mapping using clinical ultrasonic equipment. Results from finite-element simulations and a physical phantom are presented.