Objective: To present a new classification for the lumbar stenosis based on morphopathologic criteria of the lesion related to the etiology and anatomic localization. Methods: The lumbar stenosis was classified in tree types according to its localization. In type "A", the stenosis is located at the vertebra. In the sub-type "A1", the posterior wall of the vertebral body is projeted posteriorly to the canal. In the sub-type "A2", the vertebral arch narrows the canal. In type "B", the stenosis is located at the intervertebral space, frequently seen in the degenerative stenosis. In the sub-type "B1", the spine is stable and in the sub-type "B 2", a segmental instability is associated. The type "C" is the association of the type "A" with the type "B", where the "C1" is the combination of sub-type "A1" with type "B". In the "C2" the sub-type "A2" and the type "B" are combined. Conclusion: The classification can help the surgeon to identify the pathologic situation of the stenosis and can suggest the best approach when the surgical treatment is indicated.7297100Verbiest, H., Further experiences on the pathological influence of a developmental narroweness of the bony lumbar vertebral canal (1955) J Bone Joint Surg Br, 37 B, pp. 576-583Porter, W.R., Central spinal stenosis. Classification and pathogenesis (1993) Acta Orthop Scand, (SUPPL. 251), pp. 1-64Lee, C.K., Rauschining, W.G., Glenn, W., Lateral lumbar spinal canal stenosis: Classification, pathologic anatomy and surgical descompression (1988) Spine, 13 (3), pp. 313-320Arnoldi, C.C., Brodsky, A.E., Cauchoix, J., Crock, H.V., Dommisse, G.F., Edgar, M.A., Lumbar spinal stenosis and nerve root entrapment syndromes. Definition and classification (1976) Clin Orthop Relat Res, 115, pp. 4-5van Akkerveeken, P.F., Lumbar spinal stenosis. Classification and clinical presentation] (1993) Orthopade, 22 (4), pp. 202-210. , Review. GermanSenegas, J., Etchevers, J.P., Vital, J.M., Baulny, D., Grenier, F., Recalibration of the lumbar canal, a alternative to laminectomy in the treatment of lumbar canal stenosis (1988) Rev Chir Orthop Reparatrice Appar Mot, 74 (1), pp. 15-22