Hematopoiesis is coordinated by a complex regulatory network of transcription factors that involves proliferation, differentiation and maturation of a very small population of pluripotent hematopoietic stem cells with self-renewing and differentiating into various specialized and distinct blood cell types. Malfunction of transcription factors may lead to diseases such as acute myeloid leukemia (AML). The purpose of this study was to investigate the expression pattern of transcription factor mRNA in acute myeloid leukemia (AML) cells during in vitro differentiation. The 2 human leukemic cell lines HL-60 and NB4 had been used as model cell lines. Differentiation of HL-60 and NB4 cells was induced by all-trans retinoic acid (ATRA) for 4 days. Morphological changes were observed by May-Grunwald Giemsa stainings, the CD11b expression level was detected by flow cytometry. Transcription factor mRNA profiles (PU.1, C/EBPα, ε, γ, GATA-1, GATA-2) were determined by real time RT-PCR during in vitro HL-60 and NB4 differentiation; The expression level of transcription factor mRNA was relatively quantitatively analyzed by using 2(-ΔΔCT) and compared with control group. The results showed that the expression levels of PU.1 and C/EBP ε mRNA in NB4 differentiation group were 5.75 and 6.16, respectively, which were significantly higher than those in untreated group; while the expression level of C/EBPα, γ, GATA-1, GATA-2 mRNA in NB4 differentiation group were 62%, 31%, 63% and 8.7% respectively, which were significantly lower than those in untreated group; In HL-60 differentiation group, the expression levels of PU.1, C/EBPα, ε were 1.97, 1.95 and 2.35 respectively, which were significantly higher than those in untreated group; while the expression levels of C/EBPγ, GATA-1, GATA-2 in HL-60 differentiation group were 20%, 21% and 18% respectively, which were significantly lower than those in untreated group. It is concluded that dysregulation of transcription factors is a key contributing factor in the pathogenesis of acute myeloid leukemia.