High blood pressure (BP) is common in acute stroke and might be associated with a poor outcome, although observational studies have given varying results. In a systematic review, articles were sought that reported both admission BP and outcome (death, death or dependency, death or deterioration, stroke recurrence, and hematoma expansion) in acute stroke. Data were analyzed by the Cochrane Review Manager software and are given as odds ratios (ORs) or weighted mean differences (WMDs) with 95% confidence intervals (CIs). Altogether, 32 studies were identified involving 10 892 patients. When all data were included, death was significantly associated with an elevated mean arterial BP ([MABP] OR, 1.61; 95% CI, 1.12 to 2.31) and a high diastolic BP ([DBP] OR, 1.71; 95% CI, 1.33 to 2.48). Combined death or dependency was associated with high systolic BP ([SBP] OR, 2.69; 95% CI, 1.13 to 6.40) and DBP (OR, 4.68; 95% CI, 1.87 to 11.70) in primary intracerebral hemorrhage (PICH). Similarly, high SBP (+11.73 mm Hg; 95% CI, 1.30 to 22.16), MABP (+9.00 mm Hg; 95% CI, 0.92 to 17.08), and DBP (+6.00 mm Hg; 95% CI, 0.19 to 11.81) were associated with death or dependency in ischemic stroke. Combined death or deterioration was associated with a high SBP (OR, 5.57; 95% CI, 1.42 to 21.86) in patients with PICH. In summary, high BP in acute ischemic stroke or PICH is associated with subsequent death, death or dependency, and death or deterioration. Moderate lowering of BP might improve outcome. Acute BP lowering needs to be tested in 1 or more large, randomized trials.