A 60-year-old man was admitted to our hospital complaining of progressive dyspnea. On admission, he had marked hypoxemia, and his chest radiography and computed tomography (CT) showed ground glass opacities and multiple emphysematous changes in both lung fields. On examining the patient's bronchoalveolar lavage fluid (BALF). Pneumocystis carinii pneumonia (PCP) was diagnosed. A serological test for human immunodeficiency virus (HIV)-1, 2 was positive, and acquired immunodeficiency syndrome (AIDS) was diagnosed. Since the chest CT performed a month before the patient's admission to our hospital revealed ground glass opacities in both lung fields we thought that he had already developed PCP at that time. In comparison with his previous CT, the chest CT on admission showed progressive ground glass opacities and emphysematous changes. Although PCP is known to display various findings on chest radiography and CT, emphysematous changes are rarely reported in Japan. In this case we were able to confirm these changes and observe its progression using chest CT.