The etiology of idiopathic scoliosis is likely genetic. Research is proceeding to identify the responsible genes. Although genetics accounts for the majority of idiopathic scoliosis, a subset of curves occur secondary to mechanical "foundation"issues at the lumbosacral junction. The most common mechanical "foundation"issue at the lumbosacral junction is spondylolisthesis. A relationship between lumbar scoliosis and spondylolisthesis has been well documented. Modern imaging studies are providing an opportunity to cast new light on this inter-relationship. First, computerized tomography (CT) studies, and now 3-D CT studies of the lumbosacral area have been performed in an attempt to further elucidate this matter. The purpose of this paper is to provide an introduction to the topic and to present images that suggest an etiologic relationship between lumbar scoliosis and spondylolisthesis with mild asymmetric spondylolisthesis proposed as the cause of the lumbar curve.