Elevated blood pressure (BP) is a growing burden worldwide, leading to over 10 million deaths each year. In Mozambique, two national surveys of risk factors for chronic diseases were done, using the WHO STEPWISE approach, the first in 2005 and the last in 2014/2015. In this period of 10 years, the prevalence of hypertension in the adult population increased from 33.1% to 38.9% and the extremely low levels of awareness, treatment, and control did not change significantly. May Measurement Month (MMM) is a global initiative of the International Society of Hypertension aimed at raising awareness of high BP and to act as a temporary solution to the lack of screening programmes worldwide. An opportunistic cross-sectional survey of volunteers aged ≥18 years was carried out in May 2017. Blood pressure measurement, the definition of hypertension and statistical analysis followed the standard MMM protocol. Screening was conducted by volunteers, mainly in work places, markets, and religious activities, in the capital city, in most of the provincial capitals and some rural districts. About 4454 individuals were screened with a mean age of 39 years, and, after multiple imputation, 1371 (31.1%) had hypertension. Of individuals not receiving anti-hypertensive medication, 1099 (26.6%) were hypertensive. Of individuals receiving antihypertensive medication, 166 (61.6%) had uncontrolled BP. MMM17 was the largest BP screening campaign undertaken in Mozambique. These results suggest that opportunistic screening is an important tool to identify significant numbers of patients with raised BP.