Soft drinks and flavoured mineral waters contribute approximately 20% of the free sugars in the Australian diet, with around one quarter of the population consuming these beverages (1). Their contribution is higher in males and varies by age, accounting for approximately 30-35% of free sugars intake among teenagers and young adults (1). However, there is limited published data for the glycemic index (GI) of Australian soft drink products. Twelve healthy adults (age: 33.3 ± 10.2 y, BMI: 22.0 ± 2.2 kg/m2) consumed five test beverages and three reference glucose solutions, containing 25 g available carbohydrate, in a randomised, crossover study following the standardised GI testing methodology (2). In addition, participants also consumed an equal volume portion of an artificially sweetened soft drink, which did not contain any available carbohydrate. The test beverages were Coca-Cola (consumed fresh and flat), Lemonade, Lemon Lime Natural Mineral Water, sucrose solution, and Coca-Cola No Sugar. Capillary blood samples were collected at regular intervals over 2 hours and analysed for glucose concentrations. GI values were calculated. As hypothesised due to the lack of available carbohydrate, the Coca-Cola No Sugar produced a minimal postprandial glucose response (GI: 5 ± 2, p < 0.0001 compared to all other treatments and the reference glucose solution). The Lemon Lime Mineral Water, Coca-Cola, and Lemonade carbonated beverages produced similar low GI responses (GI: 51 ± 3, 53 ± 5, and 54 ± 3, respectively) that were found to be significantly lower compared to the sucrose solution (GI: 66 ± 4, p ≤ 0.024 compared to the other three treatments). When the carbon dioxide was allowed to dissipate from the Coca-Cola beverage, the GI of the product increased (GI: 53 ± 5 for Coca-Cola vs 65 ± 5 for flat Coca-Cola, p = 0.037). There was no significant difference in the GI values produced by the decarbonated Coca-Cola (GI: 65 ± 5) compared to the sucrose sugar dissolved in water (GI: 66 ± 4). Popular regular, sugar-sweetened soft drinks sold in Australia produced low GI responses. The GI responses are lower than may be expected based on their component carbohydrate, sucrose. Acidity, which is known to slow gastric emptying, is likely an underlying factor. In addition, carbonation may play a role in the lower glycemic responses observed with these beverages compared to a sucrose solution.