The prediction of bone fracture risk in individual patients based on Bone Mineral Density (BMD) measurements is of limited accuracy. This is due to the fact that bone is a complex hierarchically structured material consisting of more than four different hierarchical levels which span from the nanoup to the macro-scale [Fratzl; 2007]. Therefore the mechanical properties of bone derive from the behaviour that each individual hierarchical level exhibits during loading. Furthering our understanding of bone’s structure-function relationship [Uzel; 2010], i.e. the origin of bone material properties, is the first step towards more accurate fracture risk estimation. While several studies have dealt with the nanoand the micro-scale mechanical behaviour of the bone, little is known about the so-called sub-osteonal level. This level extends from some hundred of nanometres up to some tens of microns and includes bone single lamellae, the interlamellar areas and the cement lines. The aim of this study is to correlate nanomechanical properties of human cortical bone samples with more conventionally measured fracture toughness parameters. Using cantileverbased nanoindentation we measured cortical bone’s nanoelasticity in a spatially resolved fashion, and its distribution within the various sub-osteonal features (i.e. lamellar and interlamellar areas). First results from this study suggest a strong relationship between nanoelasticity distribution and fracture toughness within human cortical bone.