not-yet-known not-yet-known not-yet-known unknown Background: Allergic bronchopulmonary aspergillosis (ABPA), which is one of the respiratory complications of cystic fibrosis, is a hypersensitivity reaction in the lung against the antigens of the fungus Aspergillus fumigatus ( A.fumigatus). If left untreated, it may cause irreversible deteriorations in lung functions. The aim of this study is to determine the incidence of ABPA, according to years and to determine the risk factors leading to the development of ABPA by using the CF Registry System of Turkey data. Methods: The study was designed as a retrospective cohort study. Using the CF Registry System of Turkey data, the incidence of ABPA was determined and the data of 44 patients newly diagnosed with ABPA in 2022 and 132 patients with similar mutation weight and age range without ABPA diagnosis in that year were compared, and the risk factors affecting the development of ABPA were determined. Results: Low pulmonary function test values, having had at least one pulmonary exacerbation in that year and receiving intravenous antibiotic treatment, using inhaled antibiotics, having a high number of pulmonary exacerbations, having Pseudomonas aeroginosa (P.aeroginosa) colonization, having a low body mass index (BMI) and having cystic fibrosis related diabetes mellitus (CFRD) were found to be among the risk factors for the development of ABPA. Conclusions: Early recognition and treatment of ABPA is essential to prevent further damage to the lungs. Patients with frequent pulmonary exacerbations, low BMI and low pulmonary function test values, chronic colonization should definitely be considered for ABPA.