Study Design. A cross-sectional study of 745 young adolescents in the area of two Regional Health Centers in the Netherlands. Objectives. To assess the occurrence of neck and/or shoulder and back complaints in young adolescents and examine relationships with type and weight of schoolbags and other physical and psychologic risk factors. Summary of Background Data. The occurrence of back pain in children and adolescents varies from 8% to 74% in the literature. Age, gender, and certain psychological factors appear to be important risk factors. An association with heavy schoolbags has been presumed but without clear scientific evidence. Methods. A questionnaire was used, asking about complaints of back, neck, and/or shoulders and about potential risk factors including psychosomatic factors. Length and weight of the children were determined. Schoolbags were weighed, and the relative weight of the schoolbag was calculated. Results. Neck and/or shoulder complaints and also back complaints were reported by about 45% of young adolescents. Severe complaints of neck and/or shoulder were reported by 6%, and severe back complaints by 7% of the schoolchildren. The (relative) weight of schoolbags was not related to complaints of neck and/or shoulder and back. Psychosomatic factors showed the strongest association with the occurrence of neck and/or shoulder and back complaints. Conclusion. Psychosomatic factors appear to be more strongly related to the occurrence of neck and/or shoulder and back complaints than the type and weight of the schoolbag and other physical factors. The role of psychosomatic factors should be further explored in future Iongitudinal research.