We present the clinical, electrophysiological and molecular genetic findings of a 58-year-old male with genetically confirmed Huntington's disease (HD) and concurrent clinically definite ALS by El Escorial criteria. The patient presented with asymmetric upper limb amyotrophy and weakness, and subsequently developed chorea and cognitive change. Genetic testing confirmed the presence of expanded trinucleotide repeats in huntingtin, consistent with a diagnosis of Huntington's disease. This case confirms the rare coexistence of Huntington's disease and motor neuron degeneration.