Aggressive natural killer (NK) cell leukemia is a rare hematological malignancy. It often presents with a rapidly declining clinical course and a poor prognosis with a median survival of a few months. We report the case of a 23-year-old man with high fever, enlarged lymph nodes, splenomegaly, cytopenia, liver dysfunctions, coagulation disorders and hemophagocytosis. Computed tomography scan showed right lung shadow. Lung involvement was considered. Histological examination of the lung was not performed because of low platelets and coagulation disorders. Bronchoscopic examination revealed positive Epstein-Barr virus in bronchoalveolar lavage fluid. Bone marrow and lymph node phenotype showed CD56+ CD3- NK cells type. He died of respiratory failure a week after diagnosis.