Three techniques for measuring fracture healing are presented. These techniques are: (1) use of strain gauge measurements of the forces in an external fixator to determine fracture stiffness, (2) measurement of the vibration modes of a fractured long bone compared to the unfractured contralateral and (3) comparison of the ultrasound velocity across the fracture site with that for the normal unfractured bone. Examples of clinical results obtained using these techniques are presented, and the advantages and disadvantages of each technique are discussed.