Allergic bronchopulmonary aspergillosis (ABPA) is an immunologically mediated lung disease which occurs predominantly in patients with asthma, and is caused by hypersensitivity to colonized Aspergillus fumigatus. It is a chronic, relapsing disorder which can clinically range from mild asthma to fibrotic lung disease. The immunopathogenesis of the disease is not clearly understood. Early diagnosis and aggressive therapy with oral corticosteroids can prevent the development of fibrotic lung disease and are therefore, the cornerstone of management.