Abstract: (1) Background and Objective: MicroRNAs (miR) are biomarkers for assessing the extent of cardiac remodeling after myocardial infarction (MI) and important predictors of clinical outcome in heart failure. Overexpression of miR-30d appears to have a cardioprotective effect. The aim of the present study was to demonstrate whether miR-30d could be used as a potential therapeutic target to improve post-MI adverse remodeling. (2) Methods and Results: MiR profiling was performed by next generation sequencing to assess different expression patterns in ischemic vs. healthy myocardium in a rat model of MI. MiR-30d was significantly downregulated (p<0.001) in ischemic myocardium and was selected as promising target. A mimic of miR-30d was administered in the respective treatment group, whereas control group received non-functional, scrambled siRNA. To measure the effect of miR-30d on infarct area size of left ventricle, rats were randomized and treated with miR-30d or scrambled siRNA. Histological planimetry was performed 72 hours and 6 weeks after induction of MI. Infarct area was significantly reduced at 72 hours and at 6 weeks by using the miR-30d (72 hours: 22.89±7.66% vs. 35.96±9.27%, p=0.0136; 6 weeks: 6.93±4.58% vs. 12.48±7.09%; p=0.0172). To gain insight into infarct healing, scratch assays were used to obtain information on cell migration in human umbilical vein endothelial cells (HUVEC). Gap closure was significantly faster in the mimic-treated cells 20h post-scratching (12.4% more than scrambled control after 20h; p=0.013). To analyze anti-apoptotic quality of miR-30d, the ratio between phosphorylated p53 and total p53 was evaluated in human cardiomyocytes using ELISA. Under the influence of miR-30d mimic, cardiomyocytes demonstrated a decreased pp53/total p53 ratio (0.66±0.08 vs. 0.81±0.17), showing a distinct tendency (p=0.055) to decrease apoptosis rate compared to the control group. (3) Conclusion: Using a mimic of miR-30d underlines the cardioprotective effect of miR-30d in MI and could reduce the risk for development of ischemic cardiomyopathy.