The aim of this study was to evaluate the influence of intramedullary (IM) alignment used in combination with external fixation on the healing index (HI) and lengthening index (LI) in the treatment of congenital and acquired leg length discrepancies (LLD). We compared duration of the external fixator application, LLD, HI and LI between two groups of children: children in Group I underwent limb lengthening by the conventional llizarov technique, and children in Group II underwent a combination of Ilizarov technique and intramedullary alignment with Kirschner wires. Two types of LLDs were treated: congenital and acquired. We found significant differences between the two groups for duration of external fixator application and HI. Significant differences were also noted in the duration of the external fixator application, HI and LI, between patients with congenital and acquired LLDs. We also noted significant differences between Group I and Group II regarding duration of external fixator application for patients with congenital LLD and also regarding HI for both congenital and acquired types of LLD.