The aim of this study is to evaluate the influence of the external fixation associated with intramedullary nailing on the healing index in limb lengthening. Material and Methods. This study was based on a series of patients with lower and upper limb length discrepancy of different etiologies. We evaluated results of treatment in patients undergoing limb lengthening with the combination of an external circular fixator and intramedullary nailing (154 cases). The Ilizarov frame (133 cases) or Taylor Spatial Frame (21 cases) were used in combination with flexible intramedullary nailing. Results. In all the groups of patients we observed a significant reduction of the Healing Index – inferior to 30 days/cm. There were 117 complications but only 10 of them influenced on results of treatment. Finally, results are distributed according to categories: I category – 114 cases (74%), IIa – 27 cases (17.5%), IIb – 3 cases (1.9%), IIIa – 9 cases (5.7%), IVa – 1 case (0.9%). Conclusion. Flexible intramedullary nailing provides multiple advantages to a method of limb lengthening. Flexible Intramedullary Nailing, when correctly applied, respects the bone biological features which are essential for successful limb lengthening.The major effect of application of the combination of external circular fixation with FIN is significant decrease of external osteosynthesis duration.