Chronic heart failure (HF) is associated with a poor prognosis and causes considerable mortality. The aim of this study was to identify the admission characteristics useful to predict in-hospital mortality in patients admitted because of decompensation of HF. We evaluated 414 patients (age 76.2 years, 57% women). The hospital mortality rate was 11.1%. We identified 4 independent predictors of mortality: low Barthel index (odds ratio 1.03; 95% confidence interval 1.01–1.04), creatinine level >200 µmol/l (odds ratio 3.40; 95% confidence interval 1.51–7.66), peripheral oedema (odds ratio 3.12; 95% confidence interval 1.28–7.58) and the protective effect of the new onset of the disease (odds ratio 0.2; 95% confidence interval 0.08–0.77). In conclusion, the mortality of patients admitted to the hospital with an exacerbation of HF can be predicted if either poor functional capacity, renal insufficiency, peripheral oedema or previous diagnoses of HF are present. This clinical finding may help clinicians in their decision making in HF in the emergency room.