Patients with cystic fibrosis (CF) suffer from chronic infective lung disease, which determines morbidity and mortality. While bacteria, such as Pseudomonas aeruginosa, are well-known to contribute to pulmonary pathology, the relevance of fungi in CF airways remains poorly understood. The best studied fungus in CF is Aspergillus fumigatus, which frequently colonizes CF airways and causes a disease condition termed allergic bronchopulmonary aspergillosis. This review aims to provide an update on the immunological mechanisms, diagnostic approaches and therapeutic strategies for allergic bronchopulmonary aspergillosis and other Aspergillus fumigatusmediated phenotypes in CF lung disease.