BACKGROUND: More than 90% of the elementary school students in the world and most of the Iranian students use backpacks. Heavy school bags, failure to apply ergonomics standards in student's backpacks, and also mismatch between anthropometrics dimensions and schoolbag size are important issues for children's health. OBJECTIVE: The purpose of this study was to gather baseline information on the average weight carried by female primary students. It also aimed to evaluate ergonomics standards for student backpacks. METHODS: A cross-sectional study was conducted on 212 Iranian girl students aged 6-11 years. Body weight and bag weight were measured with electronic scales and body mass index calculated with WHO software 2007. A questionnaire was constructed to gather information about the backpacks. Body dimensions were measured with VICON motion Analyze system (460). Ergonomics factors were recorded using a checklist. RESULTS: 80.8% of the students used a backpack at a higher weight than recommended by the standards of 10% of body weight. The most common type of schoolbag used was double strap packs (92.5%). The majority of the students carried packs on their backs; however, most of them did not make any adjustments (79.8%). The results have shown a mismatch between the anthropometric measures and the student's backpack dimensions. CONCLUSIONS: Parents, students and school staff should be informed about these critical issues as well as suitable controls should be implemented in buying and using the bags.