We report a case of pretibial myxedema with hypothyroidism in a 52-year-old woman. She suffered from primary hypothyroidism for a period of 17 years. She was treated with a daily dose of sodium levothyroxine 0.2 mg intermittently. She had erythematous ftesh colored, hard and thickened plaque. on the left pretibial area for onr year. The histopathologic findings showed considerable amount of muci in the upper and mid dermis. Toluidine blue and alcian blue stain demonstrated an extensive deposition of dermal mucin. We treated her with a topical steroid and oral sodium levothyrcxire. (Kor J Dermatol 1993; 31(3): 408-411)