The high prevalence of overweight and obesity among schoolchildren in Brazil and worldwide has shown that strategies to promote healthy eating habits are needed. Santa Catarina was the first Brazilian State to promulgate specific legislation to regulate the food commercialized in schools (Law n 12.061/2001). The objective was to assess the functioning of school canteens in eight key municipalities of Santa Catarina, investigating whether the foods sold were in accordance with the Law. A questionnaire was completed by the principals and those responsible for the canteens. Item Response Theory was used to examine the levels of compliance with the Law. In all 345 schools took part. Of these, 156 (45%) had a canteen. The presence of a canteen was significantly higher in the private sector (p < 0.001). The majority of the canteens (n=105; 68.2%) did not sell fried snacks, soft drinks, industrialised popcorn, hard candies, lollipops and chewing gum and industrialised packaged snacks. The items which were least likely to comply with the Law were juices and the daily availability of fruits. The notice board on diet was present in only 7.1% of the establishments. Many canteens offered items of low nutritional value. The inspection of these establishments is necessary, together with educational actions targeting the proprietors of the canteens as well as the schools themselves. Training for the canteen's proprietors may constitute a strategy that will guarantee the economic viability of these establishments and the possibility of them being transforming into places of health promotion.