Objective: To investigate the relationship between the percentage of energy from fat and food and nutrient intakes at 18 and 43 months of age. Design: Diet was assessed using a 3 day unweighed food record. The children were divided into quartiles of fat intake as a percentage of energy (QFI), and food and nutrient intakes in the different QFIs were compared. Subjects: A total of 1026 children at 18 months and 863 children at 43 months, taking part in the Avon Longitudinal Study of Pregnancy and Childhood, participated. Results: At 18 months the mean (s.d.) fat intake was 31.2 (2.8) % of energy in the lowest QFI and 43.1 (2.2) % in the highest. Energy intake increased slightly with increasing QFI. The percentage of energy derived from total sugar, and in particular nonmilk extrinsic sugar fell as QFI increased, as did the ratio of polyunsaturated to saturated fatty acids. Intakes of retinol equivalents and zinc increased significantly with increasing QFI, while intakes of iron and most water soluble vitamins fell. There was a particularly marked fall in vitamin C intake as fat intake increased, from 11.8 mg=MJ in the lowest QFI, to 6.0 mg=MJ in the highest (P < 0.001). Consumption of whole milk increased substantially with percentage energy from fat, from 51 g=MJ in the lowest QFI to 116 g=MJ in the highest (P < 0.001), while consumption of fruit and fruit juice fell. The results obtained at 43 months were very similar. Conclusions: The chances of a suboptimal intake of zinc and retinol were higher at lower fat intakes. However, intakes of the fatsoluble vitamins E and D were unrelated to fat intake and intakes of iron and vitamin C fell as fat intakes increased. Some suggestions for improving diet in this age group have been given.