Postprandial hyperglycemia is a risk factor for cardiovascular disease and mortality. Serum 1,5-anhydroglucitol (1,5-AG) level is an useful clinical marker of glucose metabolism which reflects postprandial hyperglycemia more robustly compared to hemoglobin A1c (HbA1c). Relationship between serum 1,5-AG level and cardiovascular disease has been reported; however, comparison between HbA1c and 1,5-AG as markers of cardiovascular disease was not performed. We included 227 consecutive patients who underwent coronary angiography meeting the following inclusion criteria: (1) patients who had no history of coronary artery disease (CAD); (2) patients without acute coronary syndrome; (3) patients without poorly controlled diabetes mellitus; (4) patients without anemia, liver dysfunction, acute, and chronic renal failure and malnutrition; and (5) patients without adhibition of acarbose or Chinese herbal medicine. We measured HbA1c, glycoalbumin, and 1,5-AG. Serum 1,5-AG was significantly lower in patients with CAD (16.6 ± 8.50 vs. 21.1 ± 7.97 μg/ml, P < 0.001). Multivariable logistic regression analysis showed decrease in serum 1,5-AG was independently associated with the presence of denovo CAD (0.93, 95% CI 0.88-0.98, P = 0.006). Serum 1,5-AG was also independently associated with the presence of denovo CAD in patients without diabetes mellitus (0.94, 95% CI 0.88-0.99, P = 0.046). In conclusion, lower serum 1,5-AG was associated with the presence of denovo CAD. Serum 1,5-AG may identify high cardiovascular risk patients for denovo CAD in both diabetic and non-diabetic patients.