Background Leg length discrepancy alters the biomechanics of the pelvis, hip, knee, and walking. It can occur due to congenital or acquired causes. Limb length discrepancy is always managed by lengthening the shortened limb by distraction osteogenesis. The osteotomized bone can be stabilized and distracted using external or internal fixation methods. External fixation using Ilizarov is a good method, but it has all the disadvantages of external fixators. Lengthening using an external fixator with bony internal fixation by an intramedullary nail (LON) emerged to allow early fixator removal and a more comfortable consolidation period without affecting the integrity of the regeneration. Our study aimed to conclude if Illizarov and LON are efficient methods for bone lengthening and which method has fewer complications with better compliance. Patients and methods This retrospective study included 25 patients with 33 limbs were lengthened. 10 patients with 10 short femurs were lengthened by Ilizarov (group I) and 15 patients with 23 short femurs were lengthened by LON (group II). The ages ranged from 3 to 37 years for group I and 18 to 42 years for group II. Results At the end of the follow-up period, all patients for both groups gained good regenerate consolidation after lengthening. The mean length gained for the Ilizarov group was 4.9 cm and 4.7 cm for the LON group. There was an insignificant difference in percentage increase in length and consolidation index between both groups. However, there was a significant difference in external fixation period, external fixation index, and complications between both groups. Conclusion It is concluded that this study supported the previous series in the literature, which proved that LON gives a lower complication rate with better patient compliance than lengthening using Ilizarov.