Using data from the Blood Pressure and Clinical Outcome in TIA or Ischemic Stroke (BOSS) study, we aim to test the applicability and feasibility of stroke secondary prevention recommendations from the 2017 American College of Cardiology/American Heart Association guideline. Patients were categorized based on their blood pressure (BP) status at 3 months. The nonhypertension group was defined as those without a diagnosis of hypertension. The other patients were further divided into three subgroups according to office BP measured at 3-month visit (BP <130/80, 130-139/80-89, and ≥140/90 mm Hg). The primary outcome was any stroke within one year. The associations between BP status and 1-year prognosis (recurrent stroke, recurrent stroke/TIA, and poor functional outcome [modified Rankin scale score 3-6]) were estimated. Among 2341 IS/TIA patients, additional 1056 patients were classified as uncontrolled hypertension at the 90-day visit according to the new guidelines. Adjusted hazard/odds ratios (95% confidence intervals [CI]) for recurrent stroke in BP <130/80, 130-139/80-89, and ≥140/90 compared with nonhypertension group were 2.42 (95% CI: 0.87-6.76), and 4.30 (95% CI: 1.73-10.70), respectively. The prevalence of hypertension and uncontrolled BP among BOSS study population was substantially higher based on the new guidelines. BP of 130-139/80-89 did not show the worsened clinical outcomes compared with people without hypertension. Our study adds to the growing uncertainty about secondary prevention BP goal for IS/TIA patients. ©2019 Wiley Periodicals, Inc.