MicroRNAs (miRNAs) play an essential role in the development and progression of acute leukemia (AL). miR-24 promotes the survival of hematopoietic cells. However, little is known concerning the function of miR-24 in human AL. The aim of the present study was to investigate the clinical significance of miR-24 expression in AL. miR-24 expression in 147 patients with AL and 100 healthy individuals was measured by quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR). The results showed that compared with the healthy individuals, the expression of miR-24 in AL patients was significantly higher (p<0.001). In addition, miR-24 was expressed at significantly higher levels in acute myeloid leukemia (AML) patients and at significantly lower levels in acute lymphoblastic leukemia (ALL) (p<0.001). More importantly, Kaplan-Meier analysis showed that AL patients with high miR-24 expression tended to have shorter overall survival (p<0.05). In the multivariate analysis stratified for known prognostic variables, miR-24 was identified as an independent prognostic marker. Our data indicated that miR-24 upregulation was associated with poor prognosis in AL. miR-24 was identified for the first time as an independent marker for predicting the clinical outcome of AL patients.