A systematic review of the literature on the effect of tai chi exercise on blood pressure (BP) was performed. The authors searched Medline, CAB, Alt HealthWatch, BIOSIS previews, Science Citation Index, and EMBASE systems (inception through January 2007); researched Chinese Medical, China Hospital Knowledge, China National Knowledge Infrastructure, and China Traditional Chinese Medicine databases (inception to June 2005); and performed hand searches at the medical libraries of Beijing and Nanjing Universities. Clinical studies of tai chi examining BP as an outcome published in English or Chinese were included. Studies reporting only acute exercise effects were excluded. Data were extracted in a standardized manner and 2 independent investigators assessed methodologic quality. Twenty-six studies examining patients with and without cardiovascular conditions met inclusion criteria: 9 randomized controlled trials, 13 nonrandomized studies, and 4 observational studies. Study heterogeneity precluded formal meta-analyses. Twenty-two studies (85%) reported reductions in BP with tai chi (3-32 mm Hg systolic and 2-18 mm Hg diastolic BP reductions). Five randomized controlled trials were of adequate quality (Jadad score > or = 3). No adverse effects were reported. Tai chi exercise may reduce BP and serve as a practical, nonpharmacologic adjunct to conventional hypertension management.