The bone mineral areal content and the ultimate compressive strength were determined in 109 lumbar vertebrae from 36 subjects. The bone mineral areal content was related to the number, shape and localization of the Schmorl''s nodes detected in the X-rayed and sectioned vertebral bodies. One type of node, irregular in shape and localization, occurred only in the vertebrae with relatively low compressive strength. A 2nd type of Schmorl''s nodes, regular in shape and localization, did not reflect any general weakness of the vertebral bodies.