Background: Although heart failure (HF) is frequent in elderly patients, few studies have focused on patients older than 80 years. Aims: To evaluate the clinical features, treatment and long-term prognosis of HF in patients older than 80 years. Methods and results: Consecutive patients hospitalised for a first HF episode in the Somme Department (France) during 2000 were prospectively included. Of the 799 included patients, 305 (38%) were aged over 80 years. The elderly patients were mostly women with a high prevalence of atrial fibrillation, ischaemic and hypertensive heart disease. Ejection fraction (EF) was assessed in 68.5% of elderly patients and 61% had EF z 50%. Angiotensin-converting enzyme inhibitors, beta-blockers, oral anticoagulants and statins were prescribed less frequently in elderly patients. The 5-year survival in elderly patients was 19%, dramatically lower than the survival of age-and sexmatched general population (48%). Cardiovascular causes were recorded in over 60% of deaths. On multivariable analysis, cancer, renal insufficiency, old myocardial infarction, diabetes, hyponatraemia and age were predictors of mortality in elderly patients. Reduced EF was a potent predictor of death (HR 1.72, 95%CI 1.24-2.37, p = 0.001) in elderly patients. Conclusion: Long-term prognosis in HF patients older than 80 years is poor, with a dramatic excess mortality compared to the elderly general population. Life-saving drugs are largely underused in elderly HF patients.