Pulmonary involvement with Aspergillus fumigatus is varied and largely dependent on the patient's underlying pulmonary and immune status. Hypersensitivity reactions from inhalation of spores can cause acute allergic alveolitis, and bronchial colonization can cause allergic bronchopulmonary aspergillosis (ABPA). The latter is found mainly in patients with asthma or cystic fibrosis. Mycetomas develop from secondary colonization of preexisting lung cavities. Invasive and semi-invasive aspergillosis affect mostly patients with altered immune status. This essay illustrates the radiologic findings of pulmonary aspergillosis and shows the correlation between the imaging and pathologic findings.