The multi-country May Measurement Month (MMM) screening campaign aims to raise awareness on blood pressure (BP) and hypertension in individuals and communities, and measure BP, ideally, of those who had no BP measurement in the preceding year. We here report key findings from the Cameroon arm of MMM 2019. An opportunistic sample of adults (≥18 years) was included from 5 May to 5 June 2019 across 15 sites (markets, churches, homes, motor parks, workplaces, and hospitals/clinics). Data collection, cleaning, the definition of hypertension, and statistical analysis followed the standard protocol. The mean age of the 30 187 participants screened was 36.9 (SD: 14.9) years, 50.4% were female (5% of whom were pregnant), and 94.4% were screened out of the hospital/clinic settings. After multiple imputation of missing data, 6286 (20.8%) had hypertension, 24.0% were taking antihypertensive medication, and 705 (11.2%) of all participants with hypertension had controlled BP. In linear regression models adjusted for age, sex, and antihypertensive medicines use, a previous diagnosis of hypertension, a history of stroke, and use of antihypertensive medicines were significant predictors of systolic and diastolic BP levels. BPs were also significantly higher when measured in public outdoors, public indoors (diastolic BP only), workplaces, and other unspecified areas compared to hospitals/clinic settings. MMM19 is the largest ever BP screening campaign in a single month, in Cameroon and despite the limitations resulting from non-random sample selection, the opportunistic screening allows access to awareness and screening for hypertension out of the hospital/clinic settings.