Case 1 showed recurrence of hyperthyroidism accompanied by pretibial myxedema and digital clubbing 14 years after thyroidectomy for Graves' disease. Case 2 had had pretibial myxedema for the past 20 years and myxedema tuberosum at the right shoulder for the past 10 years, and on admission showed exophthalmos and digital clubbing with thyroid gland demonstrating histological picture of chronic thyroiditis. This case was in slight hypothyroidism and serum LATS was highly positive. Eight cases of E.M.O. syndrome have so far been reported in Japan, including our own. Six cases of these were males. Two cases did not show any sign of hyperthyroidism throughout their entire courses, including our Case 2 described here. Three cases had never received treatment for Graves' disease prior to the occurrence of this syndrome. The serum LATS was positive in all 5 cases thus far reported.