Bone fragility is increasingly recognized as an important complication of diabetes mellitus (DM), and both type 1 (T1DM) and type 2 (T2DM) diabetes are associated with a higher risk of fracture. The causes of bone fragility in diabetic patients are not yet fully understood; probably they are linked to low bone mineral density (BMD), poor bone quality due to the alterations in bone remodelling, microarchitecture and composition of the bone matrix. Quantitative ultrasound (QUS) is a validated, low-cost and free ionizing radiation alternative to DXA measurement of BMD for the assessment of fracture risk. The results obtained by using QUS in T1DM and T2DM have been summarized and reported in this review. QUS technique presents some benefits but also some limits. These limits could be overcome by radiofrequency echographic multispectrometry (REMS) that is a non-ionizing technology recently introduced for the assessment of bone status that can also calculate parameters related to bone quality and strength. Therefore, REMS may represent a promising approach to evaluate bone status and fragility fracture risk in DM subjects.