This is the first study that investigates the heterogeneous effects of blood pressure (BP) screening on subsequent changes in BP in a high-income country. We use data from clinical health assessments carried out in 2010 (baseline) and 2014 (follow-up) as part of a nationally-representative longitudinal study on ageing in Ireland. We focus on individuals who at baseline do not report a previous hypertension diagnosis and employ a Regression Discontinuity Design by comparing outcomes at follow-up on either side of the BP cutoff that separates normal to abnormal BP at baseline. We find that the BP screening reduces BP at follow-up, with larger and more precisely estimated effects for males, middle-age individuals (as opposed to older individuals), and individuals without public health insurance coverage.