Introduction: Neoadjuvant chemotherapy for Ewing's sarcoma has made wide resection with limb salvage possible. However, resection of iliac tumors causes proximal pelvic migration and significant leg length discrepancy. Vascularized bone autografts represent the optimal method for iliac reconstruction because they heal faster and hypertrophy sooner than nonvascularized bone grafts. The purpose of this study is to characterize the successful reconstruction of the ilium in children using the fibula free flap. Methods: Four patients underwent fibula free flap reconstruction of the pelvis after resection of the ilium, with preservation of the hip joint. All had Ewing's sarcoma of the iliac wing without evidence of metastasis (stage IIB) and had pre-operative chemotherapy. Operative records and clinic charts were reviewed. Results: Mean age was 13.4 years and follow-up 3.9 years. Mean time to union of the fibular struts was 6.8 months. All patients began toe-touch weight-bearing ambulation with crutches at 8-12 weeks. Harvested fibula lengths were 20, 25, 18, and 17 cm. Mean leg length discrepancy was 2.3 cm. No flap loss or post-operative infection occurred. All patients remained without metastasis or local recurrence. Conclusion: Successful reconstruction of the pelvic ring utilizing a triangular double-barreled fibula free flap in four children is described.