Objective: To determine the status of tumor necrosis factor (TNF) and other measures of immunity and inflammation in chronic heart failure (CHF) in the elderly. Design: Comparative survey study of subjects with heart failure and age-matched controls. Settings: University affiliated tertiary care VA Medical Center, Heart Failure Clinic. Patients: Twenty men with New York Class II and III heart failure and 17 age-matched controls. Interventions: None. Main outcome measure: Levels of lymphocyte mitogenesis, TNF, natural killer (NK) cell activity, elastase-Α₁-antitrypsin (E/Α) and cross-linked fibrin D-dimers (XDP). Results: TNF levels (p = 0.27), NK activity (p = 0.56), and lymphocyte mitogenesis (p = 0.67) were similar in patients and controls. E/Α levels were somewhat lower in CHF patients (p = 0.05) and XDP were similar (p = 0.59). However, TNF levels were significantly related to NK activity and to E/Α activity in elderly men with heart failure but not controls. XDP were positively related to NK in heart failure patients but not controls. Conclusion: TNF and other measures of immune function and inflammation do not appear to be significantly elevated in elderly patients with heart failure of moderate severity. However, significant relationships exist between TNF, NK activity, XDP and E/Α in the heart failure patients only, suggesting that immune activation and subclinical inflammation does exist in these patients.