Summary: To investigate whether the Bcl-2 gene family is involved in modulating mechanism ofapoptosis and change of cell cycle protein induced by curcumin in acute myeloid leukemia HL-60cell line and primary acute myelogenous leukemic cells, the Bcl-2 family member Mcl-l, Bax andBak and cell cycle proteins including P27kipl, P21wafl, cyclin D3 and pRbp- were selected and their ex-pression detected by SABC immuno-histochemical stain method. The attitude of sub-G1 peak inDNA histogram was determined by FCM. The TUNEL positive cell percentage was identified byterminal deoxynucleotidyl transferase ( TdT )-mediated Biotin dUNP end labeling technique. Itwas found that when HL-60 cells were treated with 25 μmol/L curcumin for 24 h, the expressionlevel of Mcl-1 was down-regulated, but that of Bax and Bak up-regulated time-dependently. Therewas significant difference in the expression level of Mcl-1, Bax and Bak between the curcumin-treated groups and control group (P＜0. 05-0. 01). At the same time, curcumin had no effect onprogress of cell cycle in primaty acute myelogenous leukemia at newly diagnosis, but could in-crease the peak of Sub-G1 (P＜0. 05), and down-regulate the expression of Mcl-1 and up-regulatethe expression of Bax and Bak with the difference being statistically significant. The expression ofP27kipl, P21wafl and pRbp- were elevated and that of cyclin D3 decreased in the presence of curcumin.These findings suggested that the Bcl-2 gene family indeed participated in the regulatory process ofapoptosisinduced by curcumin in HL-60 cells and AML cells. Curcumin can induce apoptosis ofprimary acute myelogenous leukemic cells and disturb cell cycle progression of HL-60 cells. Themechanism appeared to be mediated by perturbing Go/G1 phases checkpoints which associated withup-regulation of P27kipl, P21wafl and pRbp- expression, and down-regulation of cyclin D3.