Elevated blood pressure (BP) is a growing burden worldwide, contributing to over 10 million deaths each year. May Measurement Month (MMM) is a global initiative organized by the International Society of Hypertension aimed to raise awareness of high BP. In May 2018, we carried out an opportunistic cross-sectional survey of volunteers from different parts of the country aged ≥18 years. Blood pressure measurement followed the standard MMM protocol and statistical analysis mean of the last 2 of 3 readings was used, where these were unavailable additional imputations were performed. In total, 4883 individuals (61.0% female) were screened during the whole month of May in 91 primary and secondary health facilities, pharmacies and through an online survey. After multiple imputation, 2841 (58.2%) had HTN. Of individuals not receiving antihypertensive medication, 850 (29.4%) were hypertensive. Of those receiving antihypertensive medication, 1025 (51.5%) had uncontrolled BP. MMM18 was the largest BP screening campaign undertaken in Slovenia. A substantial number of people with possible HTN were identified and referred to general practitioners for further management. The high number of individuals with HTN, with newly diagnosed HTN and with uncontrolled BP despite medication, confirms a real need for such screening programmes in our country.