Pulmonary alveolar proteinosis (PAP) is a rare respiratory disease the character of which is accumulation of protein consisting of surfactant in alveolar spaces. PAP sometimes complicates with hematological malignancies, especially myeloid leukemia. As one of the cause of PAP, impairment of alveolar macrophage is considered. We experienced a case of PAP with chronic myeloid leukemia (CML). 41 years old woman having CML for nine years developed PAP, and was treated by bronchoalveolar lavage and imatinib. She died of respiratory failure in the end, but BAL fluid had been becoming gradually crystalline after induction of imatinib. We consider that we should try to treat to improve respiratory status not only PAP but also hematological disease.