Non-specific low back pain is a serious health and socioeconomic problem because of its frequency, chronicity, recurrence and functional and work restrictions in patients. Frequent absence of cause determination and poor correlation of the symptoms and diagnostics with imaging techniques, primarily magnetic resonance imaging and X-ray, indicate that there is a need for functional assessment in low back pain patients. Functional assessment enables quantitative measurement of functional changes which can be the cause and effect of low back pain and the reason of recurrence and work restrictions. Based on the information gathered by functional evaluation, low back pain prevention procedures can be planned and programmed and therapeutic and rehabilitation procedures can be individualised. Furthermore, functional assessment during the treatment and rehabilitation enable monitoring of the efficacy of different procedures and once the rehabilitation has been completed the evaluation of work ability. Although the significance of functional assessment for successful rehabilitation of patients with low back pain is undeniable, there is no consensus on standardisation of protocol for functional assessment. Defining valid protocols is necessary and an important precondition for a successful treatment and prevention of recurrence and development of chronic non-specific low back pain.