Background Recent studies have shown that thiazolidinediones (TZDs) could reduce in-stent restenosis and improve clinical outcomes in patients with type 2 diabetes after coronary stent implantation. It remains unclear whether nondiabetic patients with metabolic syndrome after stenting could also benefit from the treatment with TZDs.Methods Three hundred and sixty patients with metabolic syndrome who underwent coronary stent implantation were randomly assigned to a rosiglitazone group (n=180) or a control group (n=180). Patients in the rosiglitazone treatment group were treated with rosiglitazone 1 day before coronary stenting (4 mg once daily)and treatment was continued until the 9 months follow-up; while in the control group, patients were treated with placebo 1 day before the procedure and until the 9 months follow-up. Adverse events were death, myocardial infarction and urgent target vessel revascularization within 9 months after coronary stenting.Results One hundred and fifty two patients in the rosiglitazone group and 145 patients in the control group survived during the follow-up. Baseline characteristics among patients in the two groups were well balanced.There was no significant difference in target vessels or the procedure of stent implantation. Compared with the control group, treatment with rosiglitazone was associated with a lower rate of death, myocardial infarction and urgent target vessel revascularization (7.2% vs 14.5%, P=0.044).Conclusion Rosiglitazone could reduce the risk of the adverse cardiovascular event and improve clinical outcomes in nondiabetic patients with metabolic syndrome after coronary stent implantation.