In the lumbosacral spine, unilateral facet joint dislocation is an infrequent injury, which is often associated with fractures at the involved or other lumbar levels. The rare occurrence of unilateral lumbosacral facet joint dislocation without any associated fractures is presented with CT and MRI, and surgical correlation. To our knowledge, cross-sectional imaging of this injury has not previously been described in the published literature.