Relapse remains the biggest hurdle of leukemia therapy, while elucidating the molecular mechanism holds promise for the solution. Recently, microRNAs are emerging as an important regulator of cell function. In this study, we for the first time found that miR-153 was downregulated in As2O3-induced drug-resistant K562 cells. In the CD34+ K562 subpopulation, which is characteristic of leukemia stem cell and resembles the drug-resistant subgroup, miR-153 expression level was also much lower than that in the bulk. Forced expression of miR-153 only in K562 cells has no significant effects on cell growth and apoptosis. However, when cells were additionally treated with As2O3, significant greater apoptosis was observed in the miR-153 overexpressed group. Our data here suggest that strategies increasing the endogenous miR-153 might hold promise for an alternative adjuvant therapy of leukemia.