Sjogren's syndrome is an autoimmune disease that can affect multiple systems. Sjogren's syndrome with motor neuron disease is rarely reported. Herein, we describe a patient with rapidly progressive motor neuron disease secondary to Sjogren's syndrome. A 42-year-old woman was admitted to our hospital with a 2-month history of progressive limb weakness. Neurological assessment revealed fasciculation in the lower limbs and amyotrophy in the bilateral supraspinatus, interosseous, and thenar muscles. Serological examination and labial gland biopsy revealed Sjogren's syndrome. In addition, electromyography demonstrated neurogenic damage to the upper and lower limbs. The patient received a short course of high-dose corticosteroids, intravenous immunoglobulins, and immunosuppressant treatment, including a weekly dose of 0.4 g cyclophosphamide and a daily dose of 0.2 g hydroxychloroquine. However, the patient's limb weakness was further aggravated and her respiratory function was compromised. Electromyography re-examination demonstrated extensive neurogenic damage, and she was diagnosed with Sjogren's syndrome with motor neuron disease. The patient died of respiratory failure after 2 months. We suggest that more effective maintenance treatments should be sought. Further investigation is required to elucidate the association between autoimmune motor neuron disease and Sjogren's syndrome.