The objectives of this observational descriptive and crosssectional study were: 1) to describe the diet components of students from the second and third cycles of Porto Alegre public schools, 2) to verify if the institutional school meal offered was eaten by the students and 3) to verify if the presence of canteens inside the schools modifi ed the consumption.A twenty four hour opened reminder was used to evaluate the diet of 1398 students.It was observed that the institutional school meal was hardly consumed by the students, since it was offered to all of them and only 41,8% ate the meal.The consumption of items external to the school meal, were in the great majority, nutritionally weak, with high quantity of sugar and fat. These items must be considered an important factor for the non-consumption of the school meal, besides being a risk factor for the development of chronic degenerative diseases. It was verifi ed that there was an informal commerce of food items inside the four schools studied, what made impossible the comparison between schools with and without canteens. It was observed that the school environment is hardly used for the development of alimentary education activities. This study suggests that the high percentage of students that do not eat the institutional school meal should be interpreted also a waste of public funds.