Lumbar spinal stenosis is a frequent cause of low back pain. In this paper we discuss both the pathophysiology and clinical symptomatology of the disease. We also discuss advantages and limitations of plain film radiography, myelography, CT and MRI in its diagnosis. Following an analysis of the pertinent literature we try to determine the relative merit of the various radiologic procedures as to their true representation of clinical and intraoperative findings and faithful rendition of postoperative results. Until sufficient statistically valid data regarding the clinical significance of radiological findings have accumulated, surgery of lumbar spinal stenosis can only be performed after critical evaluation of the individual case.