We reported a child with cystic fibrosis (CF) who developed mucoid impaction related to allergic bronchopulmonary aspergillosis (ABPA). This is the first reported case of mucoid impaction related to ABPA in CF described to date in the literature. The case was successfully treated by corticosteroids and itraconazole therapy, but relapsed 6 months later. During exacerbation therapy, cataract formation complicated the corticosteroid treatment. We want to emphasize that 6-months therapy may be inadequate for the treatment of ABPA, and it is important to monitor for possible complications of corticosteroids therapy.