Bone substitutes are used to supplement or substitute autogenous transplantation of cancellous bone. These materials should provide a scaffold structure and support bone healing alone or in combination with other substances. In trauma surgery the indication for use of bone substitutes lies mostly in filling of small metaphyseal cancellous bone defects with high vascularization following fracture. In comparison to transplantation of cancellous bone, the advantages of bone substitutes are sufficient availability without additional donor site morbidity. Moreover, biomaterials can be stored, also ensuring ready availability. This educational article gives an overview of bone substitutes currently in clinical use.