Elevated blood pressure (BP) is the most important risk factor for cardiovascular diseases (CVDs), which are still the leading cause of mortality in Hungary. Therefore, screening programmes identifying subjects with hypertension have an important role in CVD prevention. In 2017, the International Society of Hypertension initiated May Measurement Month (MMM) aimed at raising awareness of elevated BP. Hungary joined the MMM campaigns in 2017, 2019, and 2021, and a summary of the results from 2021 is presented here. An opportunistic cross-sectional survey of volunteers aged ≥18 was carried out in September 2021. Measurement of BP, the definition of hypertension, and statistical analysis followed the standard MMM protocol. In Hungary, 30 sites were set up in primary and secondary care facilities, in pharmacies, and in malls. Both cities and villages were involved in all regions. A total of 1414 individuals were screened, and 558 subjects (39.5%) had hypertension. Out of 1065 participants not on antihypertensive medication, 209 (19.6%) had elevated BP. Among treated individuals (n = 349), 206 (59.0%) had controlled BP (<140/90 mmHg). Almost 40% of the participants had hypertension. Among untreated participants, one in five had elevated BP, while among patients on antihypertensive medication, 41% had uncontrolled BP. These results confirm the importance of screening of hypertension in untreated individuals and that efforts are required to adequately control BP in treated hypertensive patients.