The aim of this study was to evaluate the prevalence of postural changes and their relationship with BMI, pain, postures adopted in activities of the daily living (ADL), physical activity practice, gender and age (6 to 12 years). This study is characterized as cross-sectional, quantitative and descriptive. The convenience sample consisted of 840 schoolchildren. Regarding the sample characteristics, 477 (56.79%) were female aged 6-12 years (average=8.90±1.71years). Evaluations were carried out at the school premises and a questionnaire was used to collect data on gender, age, pain report, practice of out-of-school physical activities and postures adopted in ADLs. Body mass, height and posture were evaluated. Some schoolchildren (43.21%) reported not practicing physical activity outside of school, 544 (64.76%) correctly carried their backpack and 51.9% adopted correct postures to study and watch TV. Musculoskeletal pain was reported by 62.73%, and shoulders were the most affected. BMI indicated 55.6% of the sample with leanness/normal weight and 44.40% with overweight/obesity. Postural changes were present in 97.02% of students and the region with the highest number of alterations was the upper limbs. Girls presented greater number of trunk alterations (p=0.001), as well as those who did not practice physical activity (p=0.02) and alterations in the lower limbs for younger students (p=0.02) and female students (p=0.01). This study identified high prevalence of postural changes in schoolchildren.