Purpose Nonunion of femur fractures is a devastating disabling complication which is rare in children. The purpose of this study was to report the outcomes of treating infected femur nonunions in children by the Ilizarov fixator in one stage. Patients and methods The study included 13 patients with unilateral infected nonunion of the femur with an average age of 9.1 years. The nonunion duration averaged 10.69 months. Ten cases were draining nonunions, and three patients had quiescent sinuses. Associated problems include shortening in all cases (mean 3.5 cm), joint stiffness (9 cases), and angular deformity (7 cases). The quiescent cases were treated by bloodless monofocal compression-distraction. Four draining cases were treated by debridement and compression with relengthening through nonunion site. The remaining six cases were treated by bifocal technique. Results The mean follow-up duration was 60.15 months. External fixation period averaged 5.3 months. Successful union was achieved in all patients. Recurrences of infection occurred in two cases including one with refracture and another one with late pathological fracture. Other complications included pin tract infections, one delayed union, two residual angular deformities, and 6 cm residual shortening in one patient. ASAMI bone results were excellent (8 patients), good (3 patients), fair (one patient), and poor (one patient). The functional results were excellent (9 cases), good (3cases), and fair (one case). Conclusions The Ilizarov method provided a viable treatment option for treating paediatric infected femur nonunions in single stage of management with infection control in most cases and satisfactory outcomes.