Mortality in patients with chronic heart failure (CHF) is high and associated with body mass. However, the best method of assessing nutritional status in patients with CHF is not clear. We sought to demonstrate the prognostic use of a nutritional risk index (NRI) in ambulatory patients with CHF. Consecutive patients attending their first quarterly review appointment in the HF clinic were recruited. All patients had systolic left ventricular (LV) dysfunction. An NRI was calculated as: (1.5 × serum albumin [grams per liter]) + (current body weight/ideal weight). Patients were followed up every 4 months. Of the 538 patients enrolled in the study 75% were men. The patients' age was 71 ± 10 years (mean ± SD) and total median follow-up in survivors was 68 months (interquartile range 54 to 74). New York Heart Association classes II and III accounted for 60% and 27%, respectively, with 80% having moderate LV impairment or worse. Based on the NRI 23% of patients were at risk of malnutrition. Severely malnourished patients were older. There was no relation between NRI and LV function. The NRI was a univariable predictor of mortality (chi-square 25, p <0.001) and was an independent predictor of outcome in multivariable analysis (chi-square 12, p <0.001). In conclusion, the NRI is useful as a prognostic marker in patients with CHF in an outpatient setting. NRI might be of use as a surrogate marker for nutritional status in trials of dietary supplementation in CHF.