To date, few reports have attempted to correlate plain radiographic findings with computed tomography (CT) in assessing pulmonary disease in patients who have acquired immunodeficiency syndrome (AIDS). This report focuses on the most common pulmonary manifestations, with particular emphasis placed on those entities for which there is a potential role for CT. This includes identification of occult disease, especially the early diagnosis of Pneumocystis carinii pneumonia, as well as identification of unsuspected lung abscesses and cavities; characterization of diffuse parenchymal disease in patients who have abnormal radiographs; identification and characterization of mediastinal lymphadenopathy, especially in differentiating between neoplastic and non-neoplastic causes; and finally, use of CT to perform CT-guided transthoracic needle biopsies.