Objective To assess the efficacy and safety of rosiglitazone in treating type 2 diabetes mellitus (T2DM) with essential hypertension (HBP). Methods Such databases as The Cochrane Library (Issue 4, 2009), PubMed (1970 to May 2010), CBM (1978 to May 2010), CNKI (1996 to May 2010), WanFang Database (1999 to May 2010), VIP (1996 to May 2010), and Google Scholar were searched on computer, and the relevant journals such as Chinese Journal of Diabetes Mellitus were also hand researched to investigate references and collect randomized controlled trials (RCTs) about rosiglitazone (experimental group) compared with non-rosiglitazone (control group) in treating T2DM with HBP. The data were extracted according to the inclusion and exclusion criteria by two reviewers independently, the quality of the included studies was assessed according to the Cochrane Handbook for Systematic Reviews of Interventions Version 5.0, and meta-analysis was conducted by using RevMan 5.0 software. Results Among 10 RCTs involving 738 patients, one was in English from Greece, while nine were in Chinese. The average score quality of the included studies was in C level. The results of meta-analyses showed that the experimental group was more effective than the control group in lowering blood pressure levels (SBP: WMD= –17.83 mmHg, 95%CI –27.63 to –8.02; DBP: WMD=–7.81 mmHg, 95%CI –10.18 to –5.44), blood glucose levels (FBG: WMD= –1.66 mmol/L, 95%CI –3.08 to –0.23; PBG: WMD= –2.38 mmol/L, 95%CI – 4.12 to –0.64), triglyceride (TG) levels (WMD= –0.29 mmol/L, 95%CI –0.43 to –0.14), low-density lipoprotein cholesterol (LDL-C) levels (WMD= –0.76 mmol/L, 95%CI –1.02 to –0.50), insulin levels (FINS: WMD= –7.06 mU/L, 95%CI –9.47 to –4.65; PINS: WMD= –98.86 mU/L, 95%CI –116.38 to –81.34), glycosylated hemoglobin (HbA1c) levels (WMD=–0.75%, 95%CI –1.07 to –0.42), and insulin resistance index (HOMA-IR) (WMD= –1.61, 95%CI –2.18 to –1.05); the experimental group was more effective than the control group in increaseing the high-density lipoprotein cholesterol levels (HDL-C) (WMD=0.21 mmol/L, 95%CI 0.12 to 0.30), and insulin sensitivity index (ISI) (WMD=1.64, 95%CI 1.48 to 1.80); the therapeutic effect for hypertension was greater in the experimental group than in the control group (OR=9.35, 95%CI 4.76 to 18.35); there were no significant differences in cholesterol levels (TC) (WMD= –0.22 mmol/L, 95%CI –0.55 to 0.10), body mass index (BMI) (WMD= –0.26 kg/m2, 95%CI –0.86 to 0.33), heart rates (HR) (WMD=0.50 bpm, 95%CI –4.98 to 5.98), and urine albumin excretion (UAE) (WMD= –16.00mg/24h, 95%CI –37.90 to 5.90); additionally, there were also no significant differences in adverse reactions between the two groups, such as edema (OR=3.01, 95%CI 0.62 to 14.54), gastro-intestinal discomfort (OR=1.19, 95%CI 0.63 to 2.24), headache and fatigue (OR=9.79, 95%CI 0.51 to 186.95), and anemia (OR=2.38, 95%CI 0.09 to 59.90). Conclusion To treating patients suffering from T2DM with HBP, the rosiglitazone is much effective than the control group in lowering blood pressure, blood glucose and lipid, reducing insulin resistance and improving β-cell function.