We investigated the role of systolic blood pressure (SBP) in relation to in-hospital and postdischarge mortality in patients admitted with acute heart failure (AHF). The SBP of 4848 patients aged ≥18 years admitted with AHF was categorized into 5 groups: ≤90, 91 to 119, 120 to 139, 140 to 161, and >161 mm Hg. After adjusting for several confounders, multivariate logistic regression models showed that admission SBP was a significant predictor of mortality among both patients with preserved left ventricular function (defined as left ventricular ejection fraction [LVEF] ≥40%) and patients with left ventricular dysfunction (LVEF <40%). The adjusted odds ratios of in-hospital, 3-month, and 1-year mortality in the lowest SBP groups were 7.06 (95% confidence interval [CI]: 3.28-15.20; P < .001), 2.59 (95% CI: 1.35-4.96; P = .004), and 3.10 (95% CI: 2.04-4.72; P < .001) times the odds in the highest admission group (SBP > 161 mm Hg), respectively. We conclude that low admission SBP is an independent predictor of mortality in patients with AHF. The higher the admission SBP, the better the prognosis, regardless of age or LVEF.