Objective: The primary aim was to assess, the association of the quantity and quality of dietary fat intake from 6 to 12 months of age and serum lipids at 12 months. Subjects/Methods: Three hundred healthy term Swedish infants were recruited in a longitudinal prospective study at the age of 6 months; 276 remained in the study at 12 months. Food records and anthropometric data were collected monthly from 6 to 12 months; serum lipids were analysed at 6 and 12 months. Results: Swedish infants had a total fat intake within the Nordic recommendations, but intake of polyunsaturated fatty acids (PUFA) was low (5.6 percent of total energy (E%)) and intake of saturated fatty acids (SAFA) was high (15.1 E%). Higher PUFA intake was associated with lower total serum cholesterol (TC, B ¼ À0.13, P ¼ 0.003), lower low-density-lipoprotein cholesterol (LDL-C, B ¼ À0.12, P ¼ 0.004) and apolipoprotein B (B ¼ À0.03) (P ¼ 0.034) in girls but not in boys. When data from the present study were compared to data from similar studies in Finland and Iceland, it appears that the quality of the dietary fat has greater impact on serum lipid levels than the quantity of fat in the diet. Conclusions: Higher PUFA and lower SAFA intakes may reduce TC and LDL-C early in life, particularly in girls. Further, with respect to lowering serum lipid concentrations in early childhood it seems appropriate to set focus on fat quality rather than the quantity.