Back pain in children is a reality and various factors are involved in its etiology. The study’s aim was to analyze the relationship between the use and type of backpack and pain in children. An analytical observational cross-sectional study was conducted among 123 schoolchildren between 8–10 years. Data on the participants’ weight and height and their backpacks were collected, as well as the way of travel to school and their physical activity during the week. The results indicated that all backpacks were large because the backpack’s height is longer than torso length. Participants who studied in a traditional educational system (62.60%) carried backpacks that exceeded 10% of their body weight. Additionally, 31.7% of the students presented pain. There is no significant correlation between the weight or type of backpack and the pressure pain threshold collected from shoulders muscles. Participants who carried backpacks heavier than 10% of their body weight did not have more musculoskeletal pain or a lower pressure pain threshold than the others, although they did report greater fatigue. All these topics should be debated considering the student’s social environment and the backpack’s discomfort to the children, even though no relationship was found between musculoskeletal pain and backpack weight.