Durian seed flour is a source of carbohydrates that has the potential to be used to meet the carbohydrate needs of Type 2 Diabetes Mellitus (DMT-2) sufferers, but before it is used to fulfill carbohydrate needs in diabetes sufferers, an in vivo test is needed to identify the glycemic index (GI) of the flour. This study aims to determine the glycemic index of durian seed flour given orally to Sprague Dawley rats. This research was arranged in 2 steps, namely the manufacture of durian seeds flour and the glycemic index test with 5 repetitions with time variations 0; 30; 60; and 120 minutes at 3 days intervals using a glucometer. Rats were grouped into 3 groups each consisting of 2 rats. Flour was suspended in 0.1% sodium carboxymethyl cellulose (Na-CMC) at a dose of 0.5625 g, positive control was 1.125 g of glucose that given in an oral way. Data in the form of test animal blood glucose levels versus time were analyzed into the Area Under Curve (AUC) glucose levels versus AUC. GI calculations were carried out by comparing the AUC of durian seed flour to glucose AUC. The results of the research and calculations carried out obtained the GI of durian seed flour of 10.90 with low criteria category. With this GI value, it can be stated that durian seed flour has the potential as a source of carbohydrates for DMT-2 sufferers.