MiRNAs play important roles in the development of both hematopoiesis and leukemogenesis. The analysis of differential microRNA expression profiles may be a powerful tool to allow us insight on the mechanisms of childhood B-cell precursor acute lymphoblastic leukemia (pre-B-ALL). The present study provides an informative profile of the expression of miRNAs in pre-B-ALL using two independent and quantitative methods: miRNA chip and qRT-PCR of mature miRNA from 40 newly diagnosed pre-B-ALL children. Additionally, putative hematopoiesis-specific target genes were analyzed with informatics technique. Both approaches showed that miR-222, miR-339, and miR-142-3p were dramatically overexpressed in pre-B-ALL patients, and downregulation of hsa-miR-451 and hsa-miR-373* was confirmed. The results of this study offer a comprehensive and quantitative profile of miRNA expression in pre-B-ALL and their healthy counterpart, suggesting that miRNAs could play a primary role in the disease itself.