Abstract Aims A J-shaped association of cardiovascular events to achieved systolic (SBP) and diastolic (DBP) blood pressure was shown in high-risk patients. This association on oral anticoagulation is unknown. This analysis from RELY assessed the risks of death, stroke or systemic emboli, and bleeding according to mean achieved SBP and DBP in atrial fibrillation on oral anticoagulation. Methods and results RE-LY patients were followed for 2 years and recruited between 22 December 2005 until 15 December 2007. 18.113 patients were randomized in 951 centres in 54 countries and 18,107 patients with complete blood pressure (BP) data were analysed with a median follow-up of 2.0 years and a complete follow-up in 99.9%. The association between achieved mean SBP and DBP on all-cause death, stroke and systemic embolic events (SSE), major, and any bleeding were explored. On treatment, SBP >140 mmHg and <120 mmHg was associated with all-cause death compared with SBP 120–130 mmHg (reference). For SSE, risk was unchanged at SBP <110 mmHg but increased at 140–160 mmHg (adjusted hazard ratio (HR) 1.81; 1.40–2.33) and SBP ≥160 mmHg (HR 3.35; 2.09–5.36). Major bleeding events were also increased at <110 mmHg and at 110 to <120 mmHg. Interestingly, there was no increased risk of major bleeding at SBP >130 mmHg. Similar patterns were observed for DBP with an increased risk at <70 mmHg (HR 1.55; 1.35–1.78) and >90 mmHg (HR 1.88; 1.43–2.46) for all-cause death compared to 70 to <80 mmHg (reference). Risk for any bleeding was increased at low DBP <70 mmHg (HR 1.46; 1.37–1.56) at DBP 80 to <90 mmHg (HR 1.13; 1.06–1.31) without increased risk at higher achieved DBP. Dabigatran 150 mg twice daily showed an advantage in all patients for all-cause death and SSE and there was an advantage for 110 mg dabigatran twice daily for major bleeding and any bleeding irrespective of SBP or DBP achieved. Similar results were obtained for baseline BP, time-updated BP, and BP as time-varying covariate. Conclusion Low achieved SBP associates with increased risk of death, SSE, and bleeding in patients with atrial fibrillation on oral anticoagulation. Major bleeding events did not occur at higher BP. Low BP might identify high-risk patients not only for death but also for high bleeding risks. Clinical trial registration  ClinicalTrials.gov—Identifier: NCT00262600.