Correlations of age, height, weight, lordosis, and kyphosis with noninvasive spinal mobility measurements were studied in 301 men and 175 women, aged 35-55 years, who suffered from chronic or recurrent low back pain (LBP). Correlations of the different spinal movements with the degree of LBP were analyzed, with corrections for these relationships. Age had significant indirect correlations with most of the mobility measurements, but the effect of height was minor. Weight had considerable negative correlations with the mobility measurements, except lateral flexion. Lordosis and kyphosis had significant relationships with mobility in the sagittal and frontal planes. Correction for the factors analyzed only slightly reduced the correlations between spinal mobility and LPB. Thoracolumbar mobility had higher correlations with LBP than mobility of the lumbar spine. Thoracal spinal mobility alone also correlated with LBP. Lateral flexion and rotation, except for rotation in women, had stronger relationships than forward flexion and extension with LBP.