AIMS: To describe the association between age and risk factors in patients hospitalised with congestive heart failure (CHF) and to determine the effect of age on mortality. METHODS AND RESULTS: Consecutive patients admitted to 34 hospitals with CHF during a period of 2 years were registered. Mean age was 71.7+/-10.2 years, 60% were male and 63% were in NYHA class III-IV. Moderate to severe left ventricular (LV) systolic dysfunction was present in 41%. Short and long-term survival status was obtained after 30 days and 5-8 years, respectively. Older patients less frequently had LV systolic dysfunction, were under treated with ACE-inhibitors and were more often female. The prevalence of hypertension, diabetes and ischaemic heart disease increased with age, until the oldest age group (>80 years). Age was an independent predictor of short-term mortality (risk ratio (RR) per 10-year increase was 1.23 (95% CI 1.04-1.47)). Advancing age significantly increased long-term mortality (RR 1.55 (1.50-1.61)). Age interacted with the LV ejection fraction (P = 0.003). In patients with LV systolic dysfunction, the RR per 10-year increase was 1.29 (1.19-1.39) whereas in patients with preserved systolic function the RR was 1.57 (1.43-1.72, multivariate analyses). CONCLUSION: The clinical characteristics of CHF patients vary considerably with age. Elderly patients hospitalised with CHF face a very grave prognosis, particularly if their heart failure symptoms are caused by LV systolic dysfunction.