This study aims to identify major food sources of energy and macronutrients among Flemish preschoolers as a basis for evaluating dietary guidelines. Three-day estimated diet records were collected from a representative sample of 696 Flemish preschoolers (2.5-6.5 years old; participation response rate: 50%). For 11 dietary constituents, the contribution of 57 food groups was computed by summing the amount provided by the food group for all individuals divided by the total intake of the respective nutrient for all individuals. Bread (12%), sweet snacks (12%), milk (6%), flavoured milk drinks (9%), and meat products (6%) were the top five energy contributors. Sweet snacks were among the top contributors to energy, total fat, all fatty acids, cholesterol, and complex and simple carbohydrates. Fruit juices and flavoured milk drinks are the main contributors to simple carbohydrates (respectively 14% and 18%). All principal food groups like water, bread and cereals, vegetables, fruit, milk and spreadable fats were under-consumed by more than 30% of the population, while the food groups that were over-consumed consisted only of low nutritious and high energy dense foods (sweet snacks, sugared drinks, fried potatoes, sauces and sweet spreads). From the major food sources and gaps in nutrient and food intakes, some recommendations to pursue the nutritional goals could be drawn: the intake of sweet snacks and sugar-rich drinks (incl. fruit juices) should be discouraged, while consumption of fruits, vegetables, water, bread and margarine on bread should be encouraged.