A thirty-six year old male was admitted to the hospital because of fever and dyspnea. On the eighth day the patient turned out to be HIV positive. Although aggressive therapy was performed, the patient died of HIV related disease such as Pneumocystis carinii pneumonitis and CMV infection which led to multiple organ failure seventeen days after admission. We reported a case of AIDS patient who was hard to diagnose from an initial symptom of interstitial pneumonitis.