It remains unclear which blood pressure (BP) characteristics best predict cardiovascular risk in different age groups and between sexes. We leveraged data from the MORGAM (MONICA [Monitoring of Trends and Determinants in Cardiovascular Disease], Risk, Genetics, Archiving and Monograph) Project to investigate determinants of BP characteristics and their prognostic importance, in younger and older (</≥50 years) men and women. The study population comprised 107 599 individuals (53% men) aged 19 to 97 years without established cardiovascular disease, not on antihypertensive treatment, recruited between 1982 and 2008 in 38 cohorts. Covariates of BP characteristics were explored using multivariable linear regression. Prognostic importance was examined using multivariable Cox proportional-hazards regression, area under the receiver operating characteristic curve, and net reclassification improvement. The primary end point was a composite cardiovascular end point (CEP), defined as fatal or nonfatal stroke, death from coronary heart disease or nonfatal myocardial infarction. The positive association between age and systolic BP was more pronounced among individuals ≥50 years while the same was true for diastolic BP in those <50 years (P interaction <0.001). Higher systolic BP and mean BP were significantly associated with cardiovascular end point, irrespective of age group (P<0.001), but diastolic BP only demonstrated an independent relationship in the younger group (P<0.001). Brachial pulse pressure was associated with cardiovascular end point in the older age group (P<0.001). In subjects <50 years, diastolic BP significantly improved area under the receiver operating characteristic curve compared with Systematic Coronary Risk Evaluation variables (including systolic BP) alone (0.842 versus 0.840, P=0.03), enhanced continuous net reclassification improvement (0.150 [95% CI, 0.087-0.215]) and improved the prognostic value of the European Society of Cardiology/European Society of Hypertension hypertension definition (categorical net reclassification improvement=0.0255, P=0.005). In conclusion, diastolic BP may provide additional prognostic utility beyond systolic BP, in predicting composite cardiovascular events among younger individuals.