Background: This study was performed to determine the prevalence of spinal deviation such as forward head posture (FHP), exacerbated kyphosis, lumbar lordosis and scoliosis among 7 to 9 year old students in the south of Tehran Done. Methods: This cross-sectional study was performed on 2114 healthy students with an average age of 7. 99 ± 0. 81year, 1059 of which were females and 1055 were males. Individual profile, visual evaluation of the sagittalplane in relation to plumb line from lateral view, and scoliosis assessment with forward bending test (FBT) were performed. Data processing was done by21th version of SPSS. The relationship between the variables was examined by regression method. Results: The prevalence of FHP was 68. 4%, exacerbated lordosis 69. 1%, exacerbated kyphosis 68. 6%, and scoliosis 15. 7%. There is a significant relationship between FHP with age and sex, as well as the correlation between KFIS and Body Mass Index (BMI), and also between intensified lordosis with gender and BMI, ultimately derived from scoliosis with BMI. Increased kyphosis, intensified lordosis, and scoliosis were common among girls, while FHP was common in boys. Children with a low BMI were susceptible to hyper lordosis, exacerbated kyphosis and scoliosis. There was also no significant relationship between vertebral column deviations and method of the school bagcarriage. Conclusions: Regarding to the high prevalence of spinal deviations in this age group, a regular screening program to identify and treat malalignments of these children in schools is recommended. Because of significant outbreak of spinal deviations in children with low BMI, the exact attention of parents to body alignment and mass of children is essential.