Bone is a material whose properties change throughout life depending on environmental constraints. Today, imaging modalities allow clinicians to assess bone quality in adults. Unfortunately, these diagnostic tools are not suitable for children (harmful radiation, anesthesia or sedation required). Development of a clinical tool requires a good knowledge of pediatric bone tissue properties. Few studies have analyzed the properties of bone tissue during growth. This lack of reference data is due to the small amount of samples available for laboratory testings and the quality of these samples for the most taken and associated with a child's illness. The aims of this thesis are to understand the growing bone. The major interest of this work is to provide new knowledge on pediatric cortical bone. Mechanical, structural and chemical properties have been studied by the use of various techniques: tomography, microradiography, FTIRM, biochemistry, compression, ultrasonic characterization and nanoindentation. This work allowed to highlight that pediatric cortical bone evolves into a mature state: maturation of collagen cross-links, mineralization of bone tissue. These changes in the structure of the bone allows it to stiffen.