We report a case of a 71-year-old female patient with an unusual morphological variant of Philadelphia chromosome-positive, acute nonlymphocytic leukemia. The myeloblasts exhibited an extreme degree of lipid vacuolization and the serum exhibited hyperlipidemia. The initial serum triglyceride level was 756 mg/dL. There were 26,000 white blood cells per cubic millimeter with 19% myeloblasts. The bone marrow contained greater than 80% myeloblasts that were myeloperoxidase- and chloracetate esterase-positive and typed positive for OKM1 and Leu 1 myeloid cellular markers. At remission, the lipid inclusions disappeared and the serum triglyceride levels returned to normal. Both abnormalities recurred at relapse. The cause of the hyperlipidemia and lipid inclusions was most likely an acquired hyperlipoproteinemia and secondary absorption of lipids into the malignant cells.