Background <p>Chronic myeloid leukemia (CML) is an aggressive malignancy originating from hematopoietic stem cells. miRNAs play a role in physiological and developmental processes, including cellular proliferation, apoptosis, angiogenesis, and differentiation, and in CML’s prognosis, diagnosis, and treatment. This study aimed to investigate the function and possible mechanisms of action of miR-188-5p in the development and progression of chronic myeloid leukemia.</p> Methods and results <p>miRNA expression profiles were obtained from the GSE90773 dataset in the Gene Expression Omnibus (GEO). GEO2R was used to identify differentially expressed miRNAs. miRNET, miRDB, CancerSEA, GeneMANIA, and BioGRID databases were applied to assess the biological function of miRNA and target molecules in CML. RT-PCR performed validation analyses of miRNA and target molecules in CML. To determine the power of miR-188-5p expression levels to distinguish patients with CML from control, the ROC analysis was performed. miR-188-5p is significantly increased in K-562 cells, and overexpression of miR-188-5p was associated with clinicopathological features. miR-188-5p showed significantly higher AUC values (AUC = 1.0, <i>p</i> = 0.0001). The cut-off of miR-188-5p was 6.74. miRDB and mirNET predicted BUB3 and SUMO2 as a potential target gene of miR-188-5p. Additionally, increased expression of BUB3 and SUMO2 was observed in the K-562 cell. Bub3 is implicated in apoptosis and the cell cycle, whereas Sumo2 protein sumoylation and DNA binding are believed to contribute to catabolic processes.</p> Conclusions <p>Our results suggest that miR-188-5p acts as an oncomiRNA in CML pathogenesis and may be a promising therapeutic target for CML.</p>