Hypertension is a risk factor for cardiovascular disease, but the evidence for treatment and blood pressure (BP) targets in the elderly is less robust. Orthostatic hypertension is a potential risk factor for cardiovascular mortality and cognitive decline. All 85-years-olds in Linköping municipality, Sweden, were invited to a prospective birth cohort study including questionnaires, cognitive testing and physical examinations, including supine and orthostatic BP measurements. Logistic regression and Cox proportional hazard models were used to assess the impact of baseline supine and orthostatic BP on cognitive decline and all-cause mortality after 5- and 7.2 years respectively. Of 650 invited 85-year-olds, 322 were included. During follow-up, 190 persons died, and 28 persons developed cognitive decline. Neither elevated supine BP nor orthostatic hypertension were associated with cognitive decline. After adjustments, elevated supine BP was not associated with mortality in all participants, but was associated with lower all-cause mortality in participants with previously diagnosed hypertension, HR 0.59 (95% CI 0.41–0.85). Orthostatic hypertension was not associated with all-cause mortality, HR 0.56 (95% CI 0.26–1.22) after multiple adjustments. In 85-year-olds with known hypertension, elevated supine BP was associated with lower all-cause mortality. Orthostatic hypertension was not associated with cognitive decline but trended towards a lower all-cause mortality.