OBJECTIVE To explore the association between silent myocardial ischemia (SMI) and high sensitivity C-reactive protein (hsCRP) and endothelial dysfunction. METHODS 148 asymptomatic patients (103 men and 45 women) with known CAD were recruited. According to the results of ambulatory electrocardiography recording (AECG), patients were divided into two groups: SMI group and non-SMI group. All the patients underwent assessment of endothelial dependent flow mediated dilation (FMD) with high resolution ultrasound for the evaluation of endothelial function and 24-hour three-lead ambulatory electrocardiography recording for the detection of SMI. Serum hsCRP, blood glucose, HDL cholesterol, LDL cholesterol and triglycerides were measured. RESULTS Sixty of the 148 patients had SMI, with a relatively high prevalence of 40.5%. The serum concentration of hsCRP in SMI group was higher than that in non-SMI group (1.86 +/- 0.52 vs 0.91 +/- 0.36, P < 0.05) and FMD was lower in SMI group than that in non-SMI group (3.02 +/- 1.46 vs 6.36 +/- 3.79, P < 0.05). In logistic regression analysis, SMI was found to be related only to FMD (beta = -0.452, P = 0.046, OR = 1.572) and hsCRP (beta = 1.233, P = 0.036, OR = 1.632). CONCLUSIONS SMI shows a relatively high prevalence in patients with known stable CAD; it is suggested that this population still needs to be carefully evaluated with risk stratification. SMI may be caused by inflammation and endothelial dysfunction. FMD and hsCRP may serve as the surrogate markers in screening SMI in patients with known CAD.