Refractive error (RE) is one of the most common problems of visual impairment, especially among school age children. Aim The study aimed to identify the environmental risk factors of refractive errors among primary and preparatory school children in Assiut Governorate. Subjects and Method: Descriptive cross sectional research design was used. The present study was conducted during the academic year 2012-2013 involving 12 urban and rural governmental schools. Three tools were used: Tool I: An interview questionnaire. Tool II: Socio-economic scale and Tool III: applied parallel visual screening test. Results: Female represents more than half of studied students 60.9% and 59.1% for students with RE and students without, respectively. The RE was significantly higher among students living in mixed residential areas (64.3%) compared with the other residential areas. The RE was significantly higher among the group with RE exposed to near-work activity for more than 2hours / day compared with those exposed for less than 2hours/day. Conclusion: The common risk factor of R E among primary and preparatory school children are source of pollution inside and outside home and students living in mixed residential areas have higher RE compared with the other residential areas. Recommendation: Development of national programme for early detection of visual impairment, involving both preschoolers and school age children, governmental support for providing low-cost spectacles and school support to encourage children to wear their glasses and early detection of environmental risk factors causes of poor vision, especially refractive errors.