Maternal diet quality is an important and easily modifiable factor linked to offspring health. In human and animal studies, maternal obesity and impaired fetal growth are predictors of poor cardiometabolic health later in life. Carbohydrates are the most abundant macronutrient in the diet and glucose is the primary energy source for a fetus, therefore, carbohydrates quality is paramount to good metabolic health. Glycaemic index (GI) is a measure of carbohydrate quality based on postprandial blood glucose levels. Low dietary GI is associated with weight gain prevention and better metabolic health. This study compared diets high in free sugars varying in GI (glucose (high), sucrose (moderate) and isomaltulose (low)). Sucrose and isomaltulose are both glucose-fructose disaccharides, however, bond positioning alters their digestion and blood glucose response. C57BL/6 female mice were fed one of these three sugar-based isocaloric diets or an AIN93G control and mated after 5-weeks. Half the dams were culled at day 18 of pregnancy and fetuses collected (n=10 litters/diet). The remaining dams gave live birth and their pups continued on their mother’s diet until 30-weeks (n=10 litters/diet). EchoMRI determined body composition. At the end of the pre-pregnancy feeding stage all sugar dams had gained more weight than control dams (p<0.001 vs chow) and sucrose and isomaltulose dams were fatter (p<0.001 vs chow). During pregnancy all sugar dams were fatter than control dams (p<0.001 vs chow), however, only glucose dams gained more weight during pregnancy (p<0.05 vs chow). At day E18 of pregnancy, glucose pups (p<0.05 vs chow) and their placentas (p<0.001 vs chow) were heavier than fetuses from all other diets. By 30-weeks all sugar-fed female pups were heavier and fatter than AIN93G pups (p<0.01 vs chow). These results suggest that maternal carbohydrate type, regardless of GI and saccharide composition effect offspring body weight and composition in later life.