In this study, the light chain and a part of the heavy chain cDNA segment of human myeloperoxidase (MPO) were cloned with PCR and other DNA recombination techniques from HL-60 cell. The size of the cloned cDNA was 769 bp. A segment about 600bp of the cDNA was analyzed by DNA sequencing and showed no difference from the human MPO cDNA sequences published before. The MPO cDNA was used as a probe to study the MPO gene expression in leukemic cells. The Northern blot analysis and slot blot analysis of RNA isolated from leukemic cell lines and blast cells of acute leukemia showed that MPO gene expression correlated with myeloid lineage and might be used as a marker for the subclassification of acute leukemia.