Objective: Myelodysplastic syndrome (MDS) is a clonal bone marrow disorder with a high propensity to develop into acute myeloid leukemia (AML). Although abnormal microRNA expression has been implicated in MDS, the exact role of miR-181a-2-3p has not been entirely elucidated. Here, we investigated miR-181a-2-3p levels in bone marrow (BM), and described its utility as a potential indicator for MDS diagnosis and prognosis.Methods: We evaluated miR-181a-2-3p expression in BM samples of 54 newly diagnosed MDS cases, 16 sAML patients and 32 healthy donors and then assessed its association with clinical characteristics and its potential value for MDS diagnosis and prognosis.Results: Compared with healthy controls, miR-181a-2-3p levels were decreased in the total cohort of MDS patients. Additionally, in MDS patients with secondary AML (sAML), miR-181a-2-3p was over-expressed relative to levels in those without this form. The areas under the curve of receiver operating characteristic curves were 0.700 and 0.750 to distinguish MDS patients from controls and sAML from newly diagnosed MDS, respectively. Kaplan–Meier analysis showed a positive correlation between miR-181a-2-3p expression and overall survival (OS). Further, multivariate analysis indicated that miR-181a-2-3p was an independent prognostic index for MDS with respect to OS.Conclusion: Decreased miR-181a-2-3p expression in MDS patients may be considered as one of the underlying markers reflecting MDS progression and prognosis.