A combined biochemical, X-ray and electron microscopic study is presented on the molecular structure of bovine and human intervertebral disc. Positively stained electron micrographs of Type I and Type II collagen are shown to have slightly but significantly different banding patterns. New low-angle meridional patterns from different anatomical parts of the intervertebral disc are reported from native and trypsin-extracted discs. Qualitative measurements of these intensities lead to the conclusion that in the nucleus pulposus of the disc, another molecule, probably proteoglycan, is ordered on the collagen fibrils at the axial level of the gap region.