We investigated the prevalence and risk factors of prehypertension, as well as the predictors of progression from prehypertension to hypertension. To do this, we performed a systematic review and meta-analysis of cross-sectional and longitudinal studies, after unrestricted searches of PubMed and The Cochrane Library through September 2010. In addition, we reviewed references, major textbooks, and review articles. Pooled prevalence, standardized mean differences, and odds ratios were estimated by using a random-effects model.Twenty-six articles met our inclusion criteria; these included 20 cross-sectional and 6 longitudinal studies, with a total sample of 250,741 individuals. The overall pooled prevalence of prehypertension was 36%. The pooled prevalence among males was higher than that among females (40% vs 33%). The pooled standardized mean difference for body mass index was 1.37 (95% confidence interval [CI], 1.20–1.55); for total cholesterol, 8.08 (95% CI, 6.71–9.46); for low-density-lipoprotein cholesterol, 5.14 (95% CI, 3.09–7.18); and for fasting plasma glucose, 4.23 (95% CI, 3.28–5.18); all of which showed more significant results in females. The pooled odds ratio was 1.13 (95% CI, 0.93–1.37) for smoking and 0.98 (95% CI, 0.69–1.39) for drinking. In addition, factors such as older age at baseline, male sex, Mongolian race, and being overweight or obese were predictors of progression to hypertension, according to descriptive analysis.The prevalence of prehypertension was relatively high, especially for males. There were many modifiable risk factors associated with prehypertension, to which healthcare providers should pay more attention.