AIMS: To evaluate the effect of the angiotensin receptor blocker candesartan on New York Heart Association (NYHA) functional class in a broad spectrum of patients with chronic heart failure (CHF). METHODS AND RESULTS: Patients in the CHARM Programme with symptomatic CHF were randomized to placebo (n=3796) or candesartan (n=3803) and followed for a median of 38 months. NYHA class was assessed at baseline, at two weekly intervals during dose titration and 4 monthly thereafter. Patients were classified as "better", "unchanged" or "worse" at the end of the study compared to baseline. Both a simple "last visit carried forward" (LVCF) analysis and "worst rank carried forward" (WRCF) analysis (where patients who died were allocated NYHA class V) were used. In the LVCF analysis, compared to placebo, more candesartan patients improved (35.4% versus 32.5%) and fewer worsened (9.0% versus 10.3%) in NYHA class (p=0.003). The WRCF analysis also showed a better overall change in NYHA class with candesartan compared to placebo. There was no heterogeneity in the response to candesartan between the CHARM component trials. CONCLUSIONS: Candesartan improves NYHA functional class to a similar extent to other proven treatments for CHF when added to these other treatments.