A case of pretibisl myxederna in typical Graves disease was described. A 50-year-old woman revealed diffuse toxic goiter, exophthalmos, and pretibial myxedema. From light and electron microscopic findings, large amount of acid mucopolysaccharides were deposited in the stroma and fibroblssts. In spite of elevation of TBII (a kind of thyroid stimulatory factors, negative direct immunofluorescence of lesional skin and no response. of pretibial myxedema to the treatment with antithyroid drug (propylthiouracil) suggested stimulstory factors of fibroblasts might be different from those of thyroid gland.