Low back pain is a common musculoskeletal disorder affecting golfers, yet little is known of the specific mechanisms responsible for this injury. The aim of this study was to compare golf swing spinal motion in three movement planes between six male professional golfers with low back pain (age 29.2+/-6.4 years; height 1.79+/-0.04 m; body mass 78.2+/-12.2 kg; mean +/- s) and six without low back pain (age 32.7+/-4.8 years; height 1.75+/-0.03 m; body mass 85.8+/-10.9 kg) using a lightweight triaxial electrogoniometer. We found that golfers with low back pain tended to flex their spines more when addressing the ball and used significantly greater left side bending on the backswing. Golfers with low back pain also had less trunk rotation(obtained from a neutral posture), which resulted in a relative 'supramaximal' rotation of their spines when swinging. Pain-free golfers demonstrated over twice as much trunk flexion velocity on the downswing, which could relate to increased abdominal muscle activity in this group. This study is the first to show distinct differences in the swing mechanics between golfers with and without low back pain and provides valuable guidance for clinicians and teachers to improve technique to facilitate recovery from golf-related low back pain.