A 53-year-old woman with refractory acute myeloid leukemia had a cough and chest pain. Chest X-ray and computed tomography demonstrated a cavity for which antibiotics, antituberculosis and antifungal agents were not effective. A diagnosis of pulmonary aspergillosis and pulmonary alveolar proteinosis (PAP) was made on the basis of the detection of aspergillus using transbronchial lung biopsy and PAS-positive materials in the sputum. Even though some cases with PAP in hematological malignancy have been reported, the diagnosis of PAP was obtained in most of them at autopsy. In our experience three of seven cases of hematological malignancy had concomitant occurrence of aspergillosis and PAP. We should therefore pay particular attention to the possibility of PAP in patients with hematological neoplasia exhibiting pulmonary fungal infection, especially aspergillosis.