SUMMARY Three techniques for measuring spinal mobility, with special reference to ankylosing spondylitis—the spondylometer, the goniometer, and a skin distraction method—are discussed, and their accuracies and feasibilities compared. The spondylometer was found to be the quickest method, but of limited applicability to certain movements only, the goniometer the most versatile and of acceptable accuracy, and the skin distraction method inaccurate and complicated.