The aim of the study was to compare dietary habits in children at the age of 12 months with the caries status at the age of 3. In 312 children, residing in 3 different parts of Sweden, a dietary study was carried out at 12 mo. of age, and in 275 (88%) a caries examination was performed at the age of 3. At 12 months of age, higher education of the mother was positively correlated with consumption of bread, vegetables, fruit and meat and negatively with frequency of sucrose-rich foods. At the age of 3, caries was diagnosed in 16% of the children. The prevalence of cavities was related to the level of education of the mother in all 3 areas, cavities being most numerous in children whose mother had received a shorter education. A discriminant analysis showed that the equation discriminating the two a priori defined groups, one with and one without caries at the age of 3, contained a number of sucrose-rich foods. The 3-year-old children with caries had generally consumed cakes, butter, bread and sweet soups more frequently at the age of 12 months than the children in the non-caries group. The analysis thus indicated that - on the group level at least - a dietary pattern, which may be casually linked with future dental caries development, was already established at the age of 12 months. Dietary counselling, when the child is 12-18 mo. of age and based upon information about the dietary habits of the child could thus be of value to prevent caries in the preschool child.