Conflicting results from trials have caused uncertainty over the benefits of self-measured blood pressure (BP) for the management of hypertension. To assess the efficacy of self-monitored BP for the titration of antihypertensive medication, 1,182 patients with hypertension were randomly assigned to three groups in which BP was controlled by self-monitoring, by self-monitoring and telemonitoring, or by clinic measurements (usual care). The primary outcome of mean systolic BP after 12 months was lower in the two self-monitoring groups with or without telemonitoring (136.0 mmHg and 137.0 mmHg of BP, respectively) compared with usual care (140.0 mmHg). Long-term follow-up of the patients will inform about the effect on mortality, but the reduction in BP in the self-monitoring groups is estimated to reduce the risk of stroke by 20% and the risk of coronary heart disease by 10%. These findings support the use of self-measured BP to guide antihypertensive therapy.