Sarcoidosis is a multisystem granulomatous disease of unknown cause, histologically characterised by non-caseating granulomas. Sarcoidosis most commonly affects the lungs, but all organs can be involved, and there is a variable natural course from an asymptomatic state to a progressive disease. Sarcoidosis is a diagnosis of exclusion, and CT scan, endobronchial ultrasound-guided trans-bronchial needle aspiration and fluorodeoxyglucose positron emission tomography facilitate the diagnostic workup. Patients with severe symptoms or threatening organ damage require systemic treatment.