Narrowing of the vertebral canal, the lateral recess, or the neural foramina causes lumbar spinal stenosis. Stenosis results from degenerative changes that usually are superimposed on a congenitally narrowed spinal canal and can result in significant pain and disability, especially in the elderly. Signs and symptoms are related to the compression of neural and vascular elements from the limited canal space. The article reviews the anatomy and pathophysiology, clinical syndrome, diagnostic workup, and natural history of lumbar spinal stenosis to aid in proper diagnosis and treatment.