Abstract: AIM:To investigate the relationship between cardiomyocyte injury induced by hypoxia and expression of microRNA-214 (miR-214). METHODS: The expression changes of miR-214 mRNA were detected using real- time qPCR technology. Cardiomyocytes were cultured and divided into four groups: normoxia culture group (control), normoxia culture plus miR-214 inhibitor group, hypoxia culture group, and hypoxia culture plus miR-214 inhibitor group. The proliferation of cardiomyocytes in each group was evaluated by MTT assay, apoptosis rate was analyzed by flow cytometry and the lactic dehydrogenase level was measured by enzymatic analysis. RESULTS: After hypoxia culture, a significantly high expression was detected in the cardiomyocytes compared with that in control group. Hypoxia environment inhibited the proliferation of cardiomyocytes, induced apoptosis and increased lactic dehydrogenase level, an injury marker of cardiomyocytes. However, downregulation of miR-214 caused by its specific inhibitor antagonized the cardiomyocyte injury induced by hypoxia. CONCLUSION: High expression of miR-214 is related to cardiomyocyte injury induced by hypoxia and miR-214 may be an underlying target for therapy and potential diagnostic indicator.