The definition of the chronic lower back pain is established by the persistence of pain beyond 3 months of symptoms. Very often, the pain is "non specific", meaning related to a mechanical origin. The main factors inducing the pain to become chronic are individual factors, psychological factors or socio-professional factors. The socio-professional factors are often much more influential than the physical factors. The overwhelming element of treatment is physical exercise. Other methods of treatment like cognitive therapy, behavioural therapy and multidisciplinary rehabilitation can also lead to significant improvements.