The coincidence of a scoliosis with a lumbosacral spondylolysis or spondylolisthesis has remained largely ignored in the German language literature. After a survey of the foreign literature the pathogenesis of various combination forms is discussed. Primarily with the aid of oblique X-rays of lumbar scoliosis a scheme of classification involving 7 categories is worked out. The two main categories comprise unstable spondylolisthetic scolioses with increasing abnormal posture and scoliotic spondylolistheses. In these cases a lumbar scoliosis probably induces an asymmetric spondylolysis. The scheme provides the basis for discussion of conservative and surgical treatment. Taking of a standing X-ray is indispensable as a preliminary measure with every lumbar scoliosis. Oblique X-rays of the lumbosacral section appear to be equally necessary at least once. Unilateral laminar sclerosis can be a valuable sign of contralateral one-sided spondylolyses, as can scoliotic E-forms of the spinal column as well. Spondylolisthetic "scolioses" should be fused in the lumbosacral section at an early stage to prevent secondary structural curvatures. Scoliotic spondylolyses-spondylolistheses at this level should on the other hand, only be fused in serious cases accompanied by pain and progression, supplementing dorsolumbar fusion of scoliosis. In any case, the lowest lumbar vertebra must only be fused in an almost straight position. The correction should also be carried out in the case of difficult spondylolisthetic scolioses prior to the lumbosacral dorsolateral fusion using the v. Lackum transsection cast if certain, above all neurologic, findings permit.