Background: People with type 2 diabetes incorporate diabetes-specific nutritional formulas (DSNFs) in their nutrition therapy to enhance glycemic control and manage body weight. Among these formulas, the GEN-DM modified formula (GEN-DM MF) has been widely used for several years. However, the glycemic index (GI) of GEN-DM MF has not yet been determined. Objective: This study aimed to assess the GI of GEN-DM MF. Methods: Ten healthy adults with normal oral glucose tolerance were included. The plasma glucose was measured at 0 (baseline), 30, 60, 90 and 120 minutes after consuming 50 grams of glucose solution. On the subsequent two days, plasma glucose measurement was repeated using 84.46 g of GEN-DM MF containing 50 g of carbohydrates. The GI was calculated by dividing the incremental area under the glucose response curve (iAUC) of GEN-DM MF by the area under the glucose response curve of the glucose solution, then multiplying the result by 100. The glycemic load (GL) was calculated by multiplying the GI by the carbohydrate amount in one serving of GEN-DM MF (40 g) /100. Results: Six healthy men and four women with an average age of 35.80 ± 6.89 years, ranging from 28 to 44, were included in the study. The plasma glucose levels at 30 and 60 minutes following the GEN-DM MF were significantly lower than the corresponding glucose levels with p= 0.002 and 0.013, respectively. The GI and GL of GEN-DM MF were 37.75 and 9, respectively, which was classified as low GI and low GL. Conclusion: GEN-DM MF is classified as a low GI and low GL food, which could significantly lower plasma glucose levels among healthy individuals.