There have been few studies comparing blood pressure (BP)–related outcomes between users and nonusers of antihypertensive drugs. We constructed a population-based cohort of 492 540 Koreans aged 40 to 79 years, who had no preexisting cardiorenal diseases, from the National Health Insurance Service-Health Screening database. The primary composite outcome was death (or critical care unit admission) from cardiorenal causes, revascularization for myocardial infarction or stroke, and new-onset end-stage renal disease. Using time-dependent Cox models, we estimated hazard ratios according to BP and antihypertensive use, which were determined in each year of follow-up. Over 10 years of follow-up, the primary outcome occurred in 26 122 subjects, and 33 550 deaths were noted. Among nonusers of antihypertensives, the risk for the primary outcome increased linearly from a BP of 105/65 mm Hg, and the risk for all-cause mortality increased from a BP of 115/75 mm Hg. Among irregular users, the risk for the primary outcome increased as the BP increased >115/75 mm Hg. Among active users, the risk for the primary outcome increased in systolic BP <115 mm Hg and >135 mm Hg, and in diastolic BP <65 mm Hg and >85 mm Hg, and the risk for all-cause mortality increased in systolic BP <125 mm Hg and >135 or 145 mm Hg. In conclusion, this population-based study demonstrated that the associations between BP and adverse outcomes were J-shaped among active antihypertensive users, but linear or flat and then increasing among nonusers or irregular users.