Background: Atrial fibrillation (AF) is common in patients with heart failure (HF) and portends a worsened prognosis. Because of the low enrollment of African American subjects (AAs) in randomized HF trials, there are little data on AF in AAs with HF. This post hoc analysis reviews characteristics and outcomes of AA patients with AF in A-HeFT. Methods and Results: A total of 1,050 AA patients with New York Heart Association class III/IV systolic HF, well treated with neurohormonal blockade (87% β-blockers, 93% angiotensin-converting enzyme inhibitor and/or angiotensin receptor blocker), were randomized to an added fixed-dose combination of isosorbide dinitrate/hydralazine (FDC I/H) or placebo. Atrial fibrillation was confirmed in 174 (16.6%) patients at baseline and in an additional 9 patients who developed AF during the study, for a final cohort of 183 (17.4%). Comparison of patients with AF versus no AF revealed the following: mean age 61 ± 12 versus 56 ± 13 years (P <.001), systolic blood pressure (BP) 124 ± 18 versus 127 ± 18 mm Hg (P =.044), diastolic BP 74 ± 11 versus 77 ± 10 mm Hg (P =.002), creatinine level 1.4 ± 0.5 versus 1.2 ± 0.5 mg/dL (P <.001), and brain natriuretic peptide 431 ± 443 versus 283 ± 396 pg/mL (P <.001). No significant difference was observed in ejection fraction, left ventricular end-diastolic diameter, or quality-of-life scores. However, AF increased the risk of mortality significantly among AA patients (P =.018), and the use of FDC I/H reduced the risk of mortality in patients with AF (HR 0.21, P =.002). Conclusion: African Americans with HF and AF (vs no AF) were older, had lower BP, and had higher creatinine and brain natriuretic peptide levels. Mortality and morbidity were worse when AF was present, and these data suggest that there may be an enhanced survival benefit with the use of FDC I/H in AA patients with HF and AF.