Abstract Introduction In 2016, the European Society of Cardiology published a new concept of heart failure (HF) inbetween HF with reduced ejection fraction (EF) (HFrEF; EF<40%) and HF with preserved EF (HFpEF; EF>50%), the HF with mid-range EF (HFmrEF; EF between 40% and 49%). There are few studies evaluating its distinct clinical characteristics, especially in Latin America. Objective To compare clinical, laboratory and mortality characteristics in individuals with HFpEF, HFmrEF and HFrEF. Method Retrospective analysis in a prospective database of Brazilian coronary care unit admissions of patients clinically diagnosed with decompensated HF associated with serum cerebral natriuretic peptide (BNP) levels above 400 mg/dL, between September 2011 and June 2019. The clinical and laboratory characteristics of the patients, as well as the HF classification into HFpEF, HFmrEF and HFrEF, were evaluated with the first echocardiogram of the hospitalization. Analysis of variance (ANOVA) to compare means, the chi-square test for categorical variables, and the Cox regression for survival analysis were performed, with a significance level of 5%. Results The analysis included 519 patients (mean age, 74.46±12.75 years; men, 59.6%). Post-discharge follow-up was 2.94±2.55 years. Late mortality according to EF did not statistically differ between groups (53.8% x 52.1% x 57.9%, p=0.5). Multivariate analysis with Cox regression showed the following main predictors of late mortality: age (aHR 1.03; 95% CI: 1.02–1.04) and dementia (aHR 1.85; 95% CI: 1.31–2.62). The HFpEF group (aHR 1.63; 95% CI: 1.08–2.94) had higher mortality as compared to the HFmrEF (aHR 0.59; 95% CI: 0.36–0.97) and the HFrEF (aHR 0.63; 95% CI: 0.32–1.2) groups. Conclusion Factors associated with aging, such as dementia, were predictors of higher late mortality. The multivariate analysis of survival, regardless of the risk factors studied, showed a higher 3-year mortality in the HFpEF group as compared to that of the HFmrEF and HFrEF groups. Funding Acknowledgement Type of funding source: None