In ten mature rabbits two cerclage wires were placed 9 mm apart on one femur. The contralateral femora were sham-operated and served as controls. The animals were killed after 99 days and the femora subjected to four-point bending tests. All wires were embedded in callus. Strength slightly increased and stiffness was unchanged in the wired femur compared with the contralateral femur. Provided they give sufficient stability, cerclage wires may be used without fear of reducing bone strength.