Aims: Recurrence rate of low back pain is high because of the deþciency of Ôpostural and movement controlÕ. The aim was to develop a clinically useful, valid and reproducible measure for postural control in a seated position. Accuracy to control equilibrium was measured in LBP patients. Methods: Postural control was investigated in 19 chronic aspeciþc LBP patients (20- 55years, mean 42,3y) and 20 healthy controls (20-55years, mean 37,8y). An unstable seated position was created by sitting on a balance board with a swing angle of 28¡. The chair and one foot were placed on the force platform of a Balance Master, testing four difþculty levels using arm movements and occlusion of vision. Outcome was measured using force plate data and visual observations. Results: A high test-retest reproducibility was measured for the low back pain patients (87.5%) but not for the healthy controls (32.5%). Discriminant analysis of all variables divided the total group (n=39) with an accuracy 97.4% in the LBP group (n=19) and the controls (n=20). Patients show increased difþculty to maintain seated balance. Conclusions: Chronic LBPP could be recognized as having signiþcantly more difþculty to maintain control of seated balance These þndings were conþrmed during observation using a 5 point scale. Pro-prioception impairment in LBP patients can be documented in clinical practice through difþculty in sitting on a balance board.