INTRODUCTION School canteens have rules of management and supervision of menus, however has not been assessed if they are totally consumed. OBJECTIVE To assess the acceptance of food by weigh food leftovers and validation of a methodology for visual estimation in school canteens of Murcia. METHODOLOGY Participated pupils in the second and third cycle of primary education, between 8 and 12 years. The estimate of leftovers was performed by 765 food trays. Visual estimation of 300 trays was based on a categorical scale as follow: 1 (0-25%), 2 (26-50%), 3 (51- 75%), 4 (76-100%) by two dietitians and reliability was assessed with respect to the weighed food. The reliability between both methods was assessed in two samples stratified by presence or absence of school kitchen. RESULTS The first dishes with leftovers were pasta, rice and vegetable purees and was higher in those schools without kitchen (p < 0.05). Also, the second dishes poultry and fish salads and vegetables garnish. Fruit and the total sum of leftovers was higher in schools without dining menus (p < 0.05). The agreement between evaluators was high in meat dishes and salads, and substantial in vegetables, pre-cooked, omelet, pasta, fish and rice. CONCLUSIONS The leftlovers are high and there are differences in the acceptance of certain foods according to the type of menu offered. The visual scale is a reliable to measure acceptance indirectly, but training to catering staff is needed.