Diffuse fibrosing sarcoidosis represents an important predisposing factor for infection by Aspergillus sp. The clinical features and specific complications are illustrated by 3 case reports.Patients with chronic fibrosing sarcoidosis and cystic changes or cavitation in the upper lobes are the most prone to aspergillosis. Aspergilloma is the most common form and can be difficult to distinguish from chronic necrotising aspergillosis. Sarcoidosis with aspergillosis is associated with an increased incidence of respiratory failure and fatal haemoptysis. The 3 cases presented in this paper also illustrate the poor efficacy of oral antifungal drugs and bronchial embolisation. Surgery is often necessary but may be difficult on account of the extent of the lesions and poor respiratory function.In the future the use of new drugs such as voriconazole and posaconazole may improve the prognosis of this complication.Aspergillosis represents a frequent complication of diffuse fibrosing sarcoidosis which warrants early detection and treatment on account of its poor prognosis.