Background Studies of prehypertension and mortality are controversial after adjusting for other cardiovascular risk factors. This meta-analysis sought to evaluate the association of prehypertension with all-cause and cardiovascular disease (CVD) mortality. Methods The PubMed, EMBASE, Cochrane Library databases, and conference proceedings were searched for studies with data on prehypertension and mortality. The relative risks (RRs) of all-cause, CVD, coronary heart disease (CHD), and stroke mortality were calculated and presented with 95% CIs. Subgroup analyses were conducted according to blood pressure, age, gender, ethnicity, follow-up duration, participant number, and study characteristics. Results Data from 1,129,098 participants were derived from 20 prospective cohort studies. Prehypertension significantly increased the risk of CVD, CHD, and stroke mortality (RR 1.28, 95% CI 1.16-1.40; RR 1.12, 95% CI 1.02-1.23; and RR 1.41, 95% CI 1.28-1.56, respectively), but did not increase the risk of all-cause mortality after multivariate adjustment (RR 1.03, 95% CI 0.97-1.10). The difference between CHD mortality and stroke mortality was significant (P < .001). Subgroup analyses showed that CVD mortality was significantly increased in high-range prehypertension (RR 1.28, 95% CI 1.16-1.41) but not in low-range prehypertension (RR 1.08, 95% CI 0.98-1.18). Conclusion Prehypertension is associated with CVD mortality, especially with stroke mortality, but not with all-cause mortality. The risk for CVD mortality is largely driven by high-range prehypertension.