A school-based dietary survey, using seven-day records, was performed in two cohorts of Swedish adolescents; 14- and 17-year-olds. The study comprised 366 boys and 365 girls. When compared to previous studies in Sweden, a striking finding was a decrease in dietary fat intake and an increase in carbohydrate intake. However, the relative intake of saturated fat had not changed (15% of total energy). The dietary change was mainly due to an increased consumption of cereal products. There were no major differences in dietary habits or nutrient density of the food between the two age groups, or between boys and girls. The mean intakes of protein, fat and carbohydrate, expressed as a percentage of the total energy intake, were 15, 33 and 52%, respectively. The mean intakes of vitamins and minerals were low only for selenium. The boys had a high iron intake (1.5 and 1.7 times the recommended intake for 14- and 17-year-olds, respectively) while the mean iron intake for girls was 0.9 times the recommended dietary allowances in both age groups. The intake of dietary salt was higher in boys than in girls (7.7 g and 9.0 g per day in 14- and 17-year-old boys, respectively, and 5.8 g per day in both 14- and 17-year-old girls). In a long-term health perspective, this positive change in nutrient intake in adolescents may contribute to a reduction in the incidence of diet-related diseases in Sweden.(ABSTRACT TRUNCATED AT 250 WORDS)