This article aims to study the etiological and clinical profile of acute heart failure in Angola and to identify the predictors associated with in-hospital mortality. Methods: A descriptive, observational, cross-sectional study was carried out in a tertiary public hospital in Angola. Information on demographic and biological data was collected. The following variables were included: demographic, etiological, and clinical characteristics, cardiovascular risk factors, precipitating factors of cardiac decompensation, comorbidities, and complications. In the univariate analysis we evaluated absolute and relative frequency, in the bivariate analysis independent Mann-Whitney Test, T Student test, and Chi-Square, tests were used as appropriate. Results: The sample comprises 257 individuals, of which 114 (44.36%) are male. The mean age is 49.90 ± 15.95 years. Hospital mortality is 23%. Predictors of poor prognosis were male sex (56.67% vs 40.61%, p = 0.037), lower systolic, diastolic, and mean blood pressure ((mean = 115 mmHg vs 138 mmHg, p < 0.001; mean = 73 mmHg vs. 85 mmHg, p < 0.001 and mean = 87.55 mmHg vs 102.74 mmHg; p < 0.001, respectively), higher respiratory rate (mean = 26.48 vs 24.00, p = 0.013), New York Health Association (NYHA) Class IV (60.00% vs 35.03%, p < 0.001) and lower LVEF (mean = 34.90% vs 39.7%, p = 0.013) Infection as a precipitating cause of cardiac decompensation, a previous history of pulmonary TB and DCM were also associated with higher in-hospital mortality (61.66% vs 26.39%, p < 0.001; 33.33% vs 12.69 p < 0.001, and 45.00% vs 29.95%, p = 0.031; respectively). Conclusions: The results indicate that in Angola, heart failure affects young and middle-aged patients and is associated with high in-hospital mortality.