We assessed the relation between different fasting plasma glucose (FPG) levels of 5.6 to 6.9 mmol/L and the prevalence and severity of angiographic coronary artery disease (CAD) in high-risk Chinese patients. Among 512 subjects who were to undergo coronary angiography for the confirmation of suspected myocardial ischemia, 409 subjects were enrolled and categorized into 3 groups based on FPG levels: (1) </=5.5 mmol/L, (2) 5.6 to 6.0 mmol/L, and (3) 6.1 to 6.9 mmol/L. Each of these groups was further divided into subgroups by sex; the second and third groups were combined as an additional group according to the 2003 definition of impaired fasting glucose (FPG at 5.6-6.9 mmol/L). We analyzed the coronary artery stenosis score, the prevalence of angiographic CAD, and the percentage of stenosis in the 3 main arteries among the groups and examined the risk factors for angiographic CAD prevalence by logistic regression analysis. A higher correlation was observed between angiographic CAD prevalence and FPG levels of 6.1 to 6.9 mmol/L as compared with FPG levels </=5.5 mmol/L (adjusted odds ratio [OR], 2.67; 95% confidence interval [CI], 1.72-4.10; P = .011). The FPG levels of 5.6 to 6.9 mmol/L (adjusted OR, 2.57; 95% CI, 1.65-4.02; P < .001) and 5.6 to 6.0 mmol/L (adjusted OR, 2.33; 95% CI, 1.58-3.49; P = .008) were modestly correlated with angiographic CAD prevalence. The angiographic CAD prevalence, coronary artery stenosis score, and the percentage of stenosis in the left anterior descending branch increased corresponding to increasing FPG levels from </=5.5 mmol/L to 5.6 to 6.0 mmol/L to 6.1 to 6.9 mmol/L. We concluded that FPG levels of 5.6 to 6.9 mmol/L as well as of 6.1 to 6.9 mmol/L may be an independent risk factor for angiographic CAD; furthermore, there was a progressive and graded relation between FPG levels of 5.6 to 6.9 mmol/L and angiographic CAD prevalence and severity in high-risk Chinese patients.