The lumbar facet joint has long been considered a significant source of low back pain (LBP). Facet blocks with anesthetic and cortisone, and even facet denervation procedures, have been recommended as treatment for patients with LBP. The literature, however, fails to conclusively document the role of the facet in the production of LBP. Based on a review of the literature and the author's clinical studies, the following statements appear to be appropriate and defensible: (1) The lumbar facet joints are very important biomechanically. (2) The facet is not a common or clear source of significant pain. (3) The facet syndrome is not a reliable clinical diagnosis. (4) Injection of intraarticular saline into the facets in control cases is as effective as local anesthetic and steroids in relieving the patient's pain temporarily. (5) Response to facet joint injection in patients with LBP does not correlate with or predict their clinical results after solid posterior lumbar fusion, and it should not be used preoperatively as a clinical criterion in selection of patients for fusion. (6) More prospective, controlled and randomized clinical studies are recommended.