Dietary factors are suggested to be involved in recent increases in the prevalence of asthma. The differences in dietary intake of 23 asthmatic and 317 non-asthmatic students were investigated, who were chosen by multistage stratified cluster sampling. The dietary data were assessed by food frequency questionnaire and a 24-h recall form. Total calorie and fat intake were similar. Daily intake of Saturated and poly-unsaturated fatty acids, and calcium and sodium were significantly higher in asthmatics. There was no significant difference between dietary antioxidant intake of asthmatic and non asthmatics. It seems that in this age, the type of consumed fat may be more important than the amount of fat intake in inducing asthma. For accurate results, n-6 and n-3 fatty acid intake must be assessed. Higher sodium and calcium intake may also be associated with asthma. Randomized controlled trials with restricting diets can help to elucidate the results.