Cardiovascular disease is not only the leading cause of mortality in Bulgaria, but the associated mortality rate is twice the European Union average, so screening programmes that identify subjects with elevated blood pressure (BP) are of utmost importance. May Measurement Month (MMM) is an annual global initiative that began in 2017 that aims to raise awareness of high BP. Bulgaria first joined the third campaign of MMM in 2019, and an overview of the results of Bulgarian participation in MMM21 is presented in this paper. Hypertension was defined as receiving BP-lowering medications or having a systolic BP ≥ 140 mmHg or diastolic BP ≥ 90 mmHg. Statistical analysis followed the standard MMM protocol. In Bulgaria, 155 screening sites were set up in primary and secondary care facilities, in pharmacies, and outdoor spaces across 16 administrative districts. Out of 3908 individuals screened, 2896 participants (74.1%) had hypertension. Of 2896 participants with hypertension, 76.4% were on treatment of whom 48.5% had controlled BP (<140/90 mmHg). Out of 1696 participants not on antihypertensive medication, 684 (40.3%) had elevated BP. Men were found to have higher rates of undiagnosed hypertension and lower rates of control than women. By identifying almost two-thirds of the whole screened cohort with the possibility of newly diagnosed or uncontrolled hypertension, our results confirm the importance of BP screening.