Elderly patients with heart failure (HF) may be troubled by thirst, despite the fact that elderly have an impaired ability to sense thirst. The present study was undertaken to compare the intensity of thirst in patients with and without HF and to evaluate how this symptom relates to the health-related quality of life and indices of the fluid balance. Forty-eight patients (mean age 80 years) admitted to hospital with worsening HF (n = 23) or with other acute illness (n = 25) graded theirthirst and estimated their health-related quality of life (HRQoL). Serum sodium was measured and urine samples were assessed for color and electrolyte content. The HF patients reported significantly more intensive thirst (median = 75 mm) compared with those in the control group (median = 25 mm; p < 0.0001). There was no statistically significant relationship between thirst and HRQoL, which was low overall. Serum sodium and urine color did not differ significantly between the groups, but the urine of the HF patients had a lower sodium concentration and osmolality. We conclude that elderly patients with worsening HF have considerably increased thirst and, hence, intense thirst should be regarded as a symptom of HF.