Twelve patients with bone marrow necrosis were diagnosed in our hospital during the past thirteen years. All were related to malignant tumors. Bone marrow metastatic carcinoma was diagnosed in 5, suspicious metastatic carcinoma in 3, acute leukemia in 2, chronic granulocytic leukemia in 1 and malignant histiocytosis in 1. In case 1, the necrosis was secondary to gastric cancer metastasis into the bone marrow and complicated by microangiopathic hemolytic anemia; in case 3, bone marrow necrosis was the initial manifestation and a diagnosis of acute lymphocytic leukemia was finally confirmed; in case 4 of acute monocytic leukemia, bone marrow necrosis followed intramedullary chemotherapy and in case 5, marrow necrosis was secondary to chronic granulocytic leukemia. These four manifestations mentioned above have not been reported yet at home. Three cases examined by systemic 99mTe bone scan suggest that 99mTe bone scan be useful in the diagnosis of marrow necrosis. In this paper, the causes, diagnosis, treatment, prognosis and pathogenesis are discussed.