Background: Reduced right ventricular ejection fraction (RVEF) is associated with poor outcomes in patients with chronic systolic heart failure (HF). Although most HF patients are older adults, little is known about the relationship between low RVEF and outcomes in older adults with systolic HF. Methods: Of the 2008 Beta-Blocker Evaluation of Survival Trial (BEST) participants with systolic HF (left ventricular ejection fraction ≤35%) 822 were ≥65 years and had data on baseline RVEF estimated by gatedequilibrium radionuclide ventriculography. Using RVEF ≥40% (n=308) as reference, we examined association of RVEF 30-39% (n=214), 20-29% (n=206) and b20% (n=94) with outcomes using Cox regression models. Results: All-cause mortality occurred in 36%, 40%, 39% and 56% of patients with RVEF ≥40%, 30-39%, 20-29% and b20% respectively. Compared with RVEF ≥40%, unadjusted hazard ratios (HR) and 95% confidence intervals (CI) for all-cause mortality associated with RVEF 30-39%, 20-29% and b20% were 1.19 (0.90-1.57; P=0.220), 1.13 (0.84-1.51; P=0.423) and 1.97 (1.43-2.73; Pb0.001) respectively. Respective multivariableadjusted HR's (95% CI's) for all-cause mortality were 1.19 (0.88-1.60; P=0.261), 1.00 (0.73-1.39; P=0.982) and 1.70 (1.14-2.53; P=0.009). Adjusted HR's (95% CI's) associated with RVEF b20% (versus ≥40%) for cardiovascular mortality and HF mortality were 1.79 (1.17-2.76; P=0.008) and 1.97 (1.02-3.83; P=0.045) respectively. RVEF had no independent association with sudden cardiac death, all-cause or HF hospitalization. Conclusions: Abnormally low RVEF is a significant independent predictor of mortality, but not of HF hospitalization, in older adults with systolic HF. © 2010 Elsevier Ireland Ltd. All rights reserved.