Gelatinous transformation of the bone marrow in a 79-year-old patient was observed. It was associated with acute leukemia diagnosed on the biopsy of a vertebral body, indicated by previous Indium-transferrin scintigraphy. Though the lesion is usually associated with severe weight loss and cachexia, the rare cases of gelatinous transformation reported among patients with malignant disease are summarized. It is suggested that metastatic changes by blast cells in acute leukemia may lead to gelatinous transformation of bone marrow but this remains to be investigated.