We investigated the usefulness of the urinary myoinositol index (UMI) for identifying postmeal hyperglycemia in type 2 diabetics undergoing a meal tolerance test. Fifty-eight patients (18 males, 40 females) were enrolled, fasted overnight and blood collected prior to and 1 and 2 hours following the test meal. Urine was collected 2 hours after the test meal. Plasma 1,5-anhydroglucitol (1,5-AG) was measured enzymatically, and UMI with an improved enzymatic cycling method. Simple and multiple regression analyses were employed to determine correlations between plasma glucose (PG) and three PG markers; HbA_1C (Japan Diabetes Society), 1,5-AG and UMI. Study population characteristics were age 67.6±7.9 years, body mass index 24.9±3.8kg/m² and waist circumference 90.2±10.4cm. Mean concentrations for PG were 130±23mg/dL (fasting), 179±46mg/dL (1h postmeal) and 150±49mg/dL (2h postmeal), HbA1C (6.3±0.6%), 1,5-AG (11.9±5.7μg/mL) and 2h UMI (52.0±35.9mg/gCr). Correlation coefficients were calculated between 1h postmeal PG and HbA_1C (r=0.558), 1,5-AG (r=0.256), and 2h UMI (r=0.496), and 2h postmeal PG HbA_1C (r=0.605), 1,5-AG (r=0.306), and 2h UMI (r=0.606). Two hour UMI and HbA_1C (Japan Diabetes Society) were significant determinants of 2h postmeal PG. As HbA_1C reflects PG excursion during the previous 1-3 months, UMI may be a useful marker for monitoring and management of postmeal hyperglycemia in type 2 diabetics.