Acute cardiogenic pulmonary edema (ACPE) is a common and serious manifestation of heart failure (HF), representing 10-20% of all acute HF admissions. It is associated with elevated in-hospital mortality and high rates of re-hospitalization. MicroRs, like miR-30d, are of particular interest in heart failure due to their regulatory role in gene expression and potential as biomarkers for diagnosing and predicting patient outcomes, especially in high-risk cases such as ACPE. We conducted a cohort study on patients diagnosed with ACPE in the Emergency Department (ED). The circulating levels of miR-30d were analyzed at the time of hospital admission and at one-month follow-up along with other biomarkers. We enrolled 24 ACPE patients and 10 control subjects. Median age was 80.8 years (interquartile range, IQR, 8.2) in ACPE cases, and 78.5 years (IQR 9.8) in controls with a male/female ratio of 2 and 0.66, respectively. In ACPE patients, median cardiac ejection fraction was 42.5%, creatinine 1.63 mg/dL (IQR 1.24), troponin 63.5 ng/dL (58), and NT-proBNP 4243.5 pg/mL (IQR 5846) at ED evaluation. Median concentration of miR30d was 0.81 in controls, and 3.67 and 7.28 in ACPE patients at enrollment time and one month later, respectively. Re-hospitalization occurred in 7 ACPE patients in the following 3 months, and in 9 during the following year. miR-30d had a significant predictive value in assessing the risk of re-hospitalization at both 3 months and 1 year following the initial diagnosis of ACPE, while it did not in assessing the risk of death at 1 year. When compared with the other biomarkers, none of them showed a better accuracy than miR-30d. Our findings suggest that elevated levels of miR-30d are associated with an increased rate of hospital readmission at both 3 months and 1 year after discharge. Larger, multicenter studies will be needed to confirm the validity of circulating miR-30d levels as a potential biomarker useful for risk prediction in ACPE patients and its utility in improving individualized patient care.