Cohesive zone models are a powerful tool for investigations of non-linear deformation and failure processes. For the nanoscale, the use of cohesive zone models is particularly attractive as the ratio of interface to volume is high, and because locally acting bonds between material components can become relevant. The present paper demonstrates the relevance of cohesive zone modelling approaches to the development of a nano-mechanical composite model of the mineralized collagen fibril, a fundamental building block of bone. As difficulties exist in determining the independent biomechan-ical effects of collagen cross-linking using in vitro and in vivo experiments, computational modeling can provide insight into the nanoscale processes. Stress-strain curves for mineralized collagen fibrils were obtained under tensile loading for various collagen cross-linking conditions. Our model predicts that the elastic deformation mode, the yield response and the final failure of the mineralized collagen fibril may depend significantly on the state of collagen cross-linking.