Löfgren's syndrome is an acute form of sarcoidosis that is characterized by erythema nodosum (EN), bilateral hilar lymphadenopathy (BHL), and polyarthralgia or polyarthritis. This syndrome is common among white people, but is considered rare among Japanese people. We present the case of a 26-year-old Japanese woman with Löfgren's syndrome. The patient complained of polyarthritis and EN of the lower extremities that lasted for 3 months. A chest radiograph revealed BHL and nodular shadows. The angiotensin-converting enzyme (ACE) level was within the normal range. Transbronchial lung biopsy revealed a noncaseating granuloma with giant cells. Six Japanese cases of Löfgren's syndrome have been reported previously. Five of the seven Japanese patients with Löfgren's syndrome had normal ACE levels; all of them exhibited BHL. Löfgren's syndrome should be considered as a possibility when examining a patient with EN and articular symptoms, even if the patient is Japanese.