In an effort to determine the relationship between low-back pain and intraosseous hypertension, in vivo vertebral pressure measurements were performed on 19 patients. A cannulated screw was placed percutaneously into the middle of the vertebral body by a transpedicular route. Pressure measurements were recorded with the patient in various positions. Pressures were greatest in the sitting position, lowest in the prone position, and intermediate in the standing position. A correlation was found between intravertebral body pressure and patient position. Pressures were highest in the positions most commonly associated with low-back pain.