The finite element method has become an indispensable tool in biomechanics and medicine, especially when the bone or the bone-implant system are modeled numerically. Since the bone tissue material is inhomogeneous, the application of computed tomography (CT) plays a major role in the development of numerical bone models. Based on the CT scan the bone geometry can be precisely reconstructed and the denstiy of each voxel can be determined. The bone density is related to the modulus of elasticity, whereby this relation is not the same for each bone. In this research the bone is at the finite element level modeled as a linear elastic material with isotropic properties. In finite element mesh the modulus of elasticity varies with the bone density so the global bone model was modeled as inhomogeneous material. The proper choice of relation between density and modulus of elasticity of the bone has a big impact on the numerical simulation results, therefore it is necessary to validate numerical models with the experimental in vitro testing of fresh bones. In today's biomechanical investigations, animal bones are often used, mostly because of their availability. In particular, swine and sheep bones are, due to their structure, shape and dimensions, suitable for testing medical implants intended for humans. Most of density-elasticity relations in the literature are limited to the human femur, and their applicability to other human or animal bones is questionable. The aim of this doctoral thesis is in vitro experimental testing of fresh animal and human bones using the digital image correlation (DIC) method for the displacement and strain measurement. The DIC method is a modern non-contact method that enables measurement of displacement fields on the surface of a measured object and has been increasingly used in the biological tissue testing. Since as a result the method produces the displacement and strain field, it represents a quality tool for the validation of numerical models of bones. The mentioned method will give a better insight into the mechanical behavior of bones and show the mechanical response of bone to the applied load in a more realistic manner. The proposed investigation involves numerical modeling of the bone based on computed tomography and a comparison with experimental results, as well as defining the relations between density and modulus of elasticity for certain types of bones. The greater part of the investigation will be carried out on fresh swine and sheep bones primarily because of their accessibility.