This is the case of a 71 year old male who developed multiple myeloma (MM) and chronic myelogenous leukemia (CML) within a two year period. The patient initially presented with osteolytic lesions of the lumbar spine, and following the initial work-up a diagnosis of multiple myeloma with an IgG kappa paraproteinemia was made and appropriate treatment was given. Two years later the patient developed a progressively worsening leukocytosis which was found to be due to Philadelphia Chromosome (Ph¹) positive CML. The occurrence in the same patient of two distinct hematologic malignancies suggests a neoplastic transformation of a pluripotent stem cell. A review of the literature appears to support the existence of a relationship between MM and CML as well as a relationship between MM and the myeloproliferative disorders.