Most spinal arachnoid cysts are asymptomatic and detected incidentally during magnetic resonance imaging or myelography. The etiology of intraspinal arachnoid cyst is not yet clear. We present two children with three spinal extradural arachnoid cysts and each cyst protruded from a separate dura defect. In both patients, plain radiographs demonstrated widening of the interpedicular distance, which suggested progressive widening of the spinal bony canal. Limited laminectomy was performed to remove the intraspinal cysts. Separate dura defects, the apparent predisposing factors, were also found and repaired. The patients completely recovered neurologically. Radical cyst removal and dura defect closure are the surgical intervention of choice in patients with symptomatic extradural arachnoid cyst.