Sarcoidosis is a systemic granulomatous disease that primarily affects the lung and lymphatic systems. Sarcoidosis patients commonly have spontaneous remission and good prognosis. But some patients show chronic, progressive and life-threatening conditions. Determination of prognosis based on the initial clinical presentation is important for the treatment. In this article, we review natural history, prognosis and the factors related prognosis of sarcoidosis patients in Japan. Shadows on chest radiograph were cleared in 76% of patients for 10 years. Approximately 15% of patients had severe organ dysfunction. In 60% of the sarcoidosis autopsy cases, the causes of death were attributed to organ involvement of sarcoidosis. Adverse prognostic factors are advanced age at onset, the presence of symptoms, extrathoracic involvement and treatment of corticosteroids.