Juvenile muscular atrophy of the distal upper extremity (Hirayama disease) is a benign and non-progressive motor neuron disease. Application of a cervical collar is believed to prevent progression of symptoms in the early stages, but there is no effective therapy for the advanced disease. We found that tendon transfer improved the activities of daily living (ADL) of a patient with advanced Hirayama disease. An operative reconstruction can be valuable, even in patients with Hirayama disease who have developed impaired ADL due to extensive intrinsic hand muscle atrophy.