Sarcoidosis is a systemic inflammatory disease usually presenting with pulmonary symptoms. However, acute arthritis could be the presenting sign of sarcoidosis. We present a 47-year-old man with bilateral arthritis of the ankles, erythema nodosum and bilateral hilar adenopathy on the chest X-ray. This triad is known as Löfgren's syndrome, a form of acute sarcoidosis. He was first treated with an NSAID, followed by a short course of prednisone because of persisting symptoms. After six weeks the patient was asymptomatic. Further investigation showed no decline in pulmonary function. Acute arthritis in patients with sarcoidosis with or without the complete Löfgren's syndrome has a good prognosis. Usually the signs and symptoms will disappear within a few months. Unlike other forms of sarcoidosis, Löfgren's syndrome does not require histological proof of non-caseating granulomas.