Systemic sclerosis is associated with a broad spectrum of autoimmune thyroid diseases. The association between systemic scleroderma and hypothyroidism is well established. However, there have been very few reports concerning the association between hyperthyroidism and systemic scleroderma. We experienced a patient with Graves' disease who presented with muscle weakness and the patient was finally diagnosed with systemic sclerosis via pathological examination of the muscle. We describe here a rare case of systemic sclerosis associated with Graves` disease.