A case report of two patients with Arnold-Chiari malformation (ACM) with signs of sleep apnoea is presented. The first subject presented with respiratory failure due to obstructive sleep apnoea which worsened during respiratory infection. The continuous positive airway pressure treatment of this subject failed because of bad compliance. The second patient showed a variety of typical ACM symptoms and symptomatic central sleep apnoea. The CPAP treatment in this patient was successful. A review of literature describing sleep disordered breathing in patients with ACM is discussed.