Although beta-adrenergic-receptor antagonists reduce morbidity and mortality in patients with mild-to-moderate chronic heart failure, their effect on survival in patients with more advanced heart failure is unknown. A total of 2708 patients with heart failure designated as New York Heart Association (NYHA) functional class III (in 92 percent of the patients) or IV (in 8 percent) and a left ventricular ejection fraction of 35 percent or lower were randomly assigned to double-blind treatment with either bucindolol (1354 patients) or placebo (1354 patients) and followed for the primary end point of death from any cause. The data and safety monitoring board recommended stopping the trial after the seventh interim analysis. At that time, there was no significant difference in mortality between the two groups (unadjusted P=0.16). The results presented here are based on complete follow-up at the time of study termination (average, 2.0 years). There were a total of 449 deaths in the placebo group (33 percent) and 411 deaths in the bucindolol group (30 percent; adjusted P=0.13). The risk of the secondary end point of death from cardiovascular causes was lower in the bucindolol group (hazard ratio, 0.86; 95 percent confidence interval, 0.74 to 0.99), as was the risk of heart transplantation or death (hazard ratio, 0.87; 95 percent confidence interval, 0.77 to 0.99). In a demographically diverse group of patients with NYHA class III and IV heart failure, bucindolol resulted in no significant overall survival benefit.