Aspergillus fumigatus is commonly found in the airways of patients with cystic fibrosis (CF), and allergic bronchopulmonary aspergillosis (ABPA) is the most recognized associated clinical condition. However, accurate diagnosis remains challenging, and there is a paucity of clinical trials to guide clinical management of fungal disease. The aim of this survey was to assess the variability in current practice across the UK in diagnosis and management of fungal lung disease in CF patients. A 21 question anonymous online survey was sent to 94 paediatric and adult CF consultants in the UK. The response rate was 60.6% (32 adult physicians, 25 pediatricians) with 55 full and 2 partially completed surveys. For a first diagnosis of ABPA 20 (35.1%) treat with prednisolone alone, 38 (66.7%) use prednisolone with itraconazole and 2 (3.5%) choose voriconazole. Only 5 (8.8%) treat with prednisolone alone for a 1st relapse, 33 (58%) used prednisolone with itraconazole. To reduce treatment, 21 (36.8%) decrease steroids to zero over time and maintain azole therapy, 18 (31.6%) stop the azole and steroid after a fixed time, and 5 (8.8%) stop the azole after a fixed time and maintain a small steroid dose. Thirty-eight (66.7%) respondents believe Aspergillus colonization of the airway can cause clinical deterioration, and 37 (66.1%) would treat this. Scedosporium apiospermum infection has been diagnosed and treated by 35 (61.4%) of respondents. Results of this survey highlight the variance in clinical practice and the limited evidence available to guide management of fungal infection in CF.