In a 4-year period, 18 patients underwent callus distraction of the femur or tibia with the use of a unilateral external fixator. Twelve patients had post-traumatic bone loss resulting from complex lower-limb fractures. The bony defect was located in the tibia in 11 cases and in the femur in one case. All patients had major associated soft-tissue lesions. The length of the bony defect averaged 6.25 cm. Eight fractures were infected at the beginning of treatment. Six other patients underwent callus distraction for reasons of limb shortening. Five femora and one tibia were lengthened. The average increase in length was 6.5 cm. There were no fixator-related complications during distraction. The rate for the lengthening and consolidation phase was 49 days for 1 cm of length. Complications consisted of angulatory deformities in 6 cases, infections in four cases, fractures at the docking site in four cases and a fracture of the callotasis in one case. Nine patients underwent reosteosynthesis: planned secondary nailing after callus distraction was carried out in six patients. Three patients underwent plating at the docking site. The follow-up examination after bone transport showed a good-to-excellent outcome in 7 out of 11 patients. The outcome was satisfactory in 4 cases. Results after limb lengthening were good to excellent in all cases. The unilateral external fixator is, in our opinion, a convenient stabilization device and permits appropriate bone transportation for distraction osteogenesis. Alignment control during distraction, however, was difficult to manage in some cases. At the time of docking, reosteosynthesis by intramedullary nailing represents a viable alternative for further external fixation if the limb is free of infection.