Diabetes mellitus has emerged as a novel risk factor for fragility fractures. While in type 1 diabetes the 3-fold overall relative risk for fractures may mostly derive from low bone mineral density (BMD) likely due to the lack of the bone-anabolic hormones, in type 2 diabetes, the fracture risk is increased about 2-fold, despite a normal or even higher BMD. This suggests that bone fragility in each form of diabetes develops by distinct mechanisms that to date remain largely unknown and may require an individualized approach for effective treatment. As the diabetes epidemic is increasing worldwide with aging, and the fractures that are associated with diabetes cause an increase in morbidity, mortality, and healthcare costs, diabetes-induced osteoporosis imposes a significant burden on our society and our healthcare system. FIDELIO offers a comprehensive, multidisciplinary training program for Early Stage Researchers (ESRs) in this emerging field, unravelling i) the biological mechanisms that contribute to altered bone quality parameters with subsequent bone fragility in diabetes, ii) identify predictive markers for patient stratification and individualized interventions, and iii) develop novel imaging techniques to determine bone quality aspects. The research will employ well-defined patient cohorts, preclinical models of diabetic bone disease, in vitro studies, genetic databases, artificial intelligence, and cutting-edge imaging technologies in a highly collaborative and interdisciplinary environment. ESRs will be trained through individual research projects, secondments, residential courses, and webinars provided by a broad range of experts, including bone biologists, clinicians, epidemiologists, geneticists, engineers and entrepreneurs, as well as companies supporting this important area of research. The joint training programme will also develop transferable and entrepreneurial skills to help the ESRs succeed in their choice of professional future.