Leigh syndrome is a rare progressive neurodegenerative mitochondrial disorder. Over 75 pathogenic mutations have been identified in both the mitochondrial and nuclear genomes. Leigh syndrome can be diagnosed based on clinical manifestations, physical and biochemical examinations, and brain magnetic resonance imaging results. Patients with Leigh syndrome classically present in early childhood with developmental regression, ataxia, and hypotonia with subsequent respiratory and brainstem dysfunction. However, the clinical course of Leigh syndrome is heterogeneous with significant differences in age of onset, symptom severity and prognosis. Here, we report a case of Leigh syndrome with cardiac arrest as initial presentation, and identified the novel mutation of NDUFS1 gene.