Back pain has become a real public health concern both for adults and children. In general, patients complain of moderate pain. While the topic was long ignored by the scientific community, the number of publications has increased over the last three Years. We reviewed the literature to separate real evidence from speculations. Recognized risk factors for spinal pain are: female gender, poor general status, family history of back pain, particular psychological patterns, time spent sitting watching television, history of spinal trauma, intense physical activity, practicing competition sports, and age (more frequent in adolescents than children). Several recent papers have drawn attention to the role of the weight of the school backpack in children, particularly when its weight exceeds 20% of the child's body weight. Many children carry heavy backpacks which for some may weigh 30% to 40% of their body weight. Several groups have estimated that the maximum should be 10% of the body weight. It appears that time spent carrying the backpack as well as its weight is an important factor favoring back pain. Backpacks can injury the head or face, as well as the hands, the elbow, the wrist, the shoulder, the foot and the ankle. Back trauma is observed as the sixth most common injury. The 'weak point' is the shoulder and not the back. A poorly positioned backpack can modify posture and gait. Carrying the backpack with two shoulder straps affects posture and gait less than carrying it on one shoulder. The posture of the spine changes when the weight of the backpack increases. This is probably one of the reasons why many parents who consult believe that there is a relationship between the weight of the backpack and scoliosis or kyphosis, observed in many of their children. It is proven that adolescents who suffer from back pain will probably have chronic back pain as adults, but there is not evidence to our knowledge demonstrating a relationship between the development of spinal deviation and the weight of the backpack. Recent studies have been conducted to design backpacks allowing a better weight distribution and comfort. This type of backpack appears to have a limited benefit. Furthermore, the question of mode must not be ignored for children and adolescents. Backpacks with one sack in front and one in back certainly provide better weight distribution but are they acceptable for children and adolescents?