Objects: A rare case of cerebellopontine angle arachnoid cyst leading to congenital peripheral facial palsy was presented. Clinical Presentation: A 1-year-old girl presented with peripheral facial paralysis since birth. Computed tomography and magnetic resonance imaging revealed left cerebellopontine angle arachnoid cyst causing moderate displacement of the brain stem. Intervention: Retrosigmoid suboccipital craniotomy was performed and microsurgical resection of the cyst wall and fenestration of the cyst to the basal cisterns were achieved. Conclusions: Cerebellopontine angle arachnoid cyst should be considered as a potential cause of congenital peripheral facial palsy. Copyright (C) 2004 S. Karger AG, Basel.