The aim of our study was to evaluate the usefulness of functional assessment in very old patients admitted for heart failure. We assessed 188 patients aged >79 years. Their mean age was 84.6 (3.5) years, and 67% were female. Twenty-five patients (13%) died. Mortality was higher in those with more severe disability, with more comorbid conditions (as determined by the Charlson index), and with a low hematocrit and a high creatinine level. Logistic regression analysis showed that the Barthel index, the Charlson index, and the serum creatinine level were statistically significant factors. Functional assessment may help in the identification of elderly patients at a higher risk of death following hospital admission for heart failure.