The purpose of the study was to identify the current status of backpack weight in primary schoolchildren in Colima, Mexico, in relation to gender, school grade level, and body mass index. A cross-sectional study was conducted on 240 randomly selected children from 20 primary schools. The participating children's parents signed statements of informed consent. Descriptive statistics, the ?[superscript 2] test, Student's t-test, and Kruskal-Wallis test were used. The mean age was 8.55 ± 2 years (range: 5-12 years). Seventy-eight percent of the schoolchildren presented with a backpack overload that was greater than 10% of their body weight. No significant differences were found in relation to gender. Four out of every five schoolchildren presented with backpack overload, exposing them to a potential health problem. Education and public policy prevention strategies for this situation should be implemented in Mexico and other regions of the world with the same problem.