A case of spondylolisthesis in an infant is herein described. The typical forward dislocation of the body of the fifth lumbar vertebra is present. There is a bilateral defect in the pedicles visible in the anteroposterior and lateral roentgenograms. There are no symptoms referable to the vertebral dislocation. The discovery of this case of congenital spondylolisthesis makes it likely that others are also congenital, and necessitates a more careful and critical study of this type of deformity in relation to its exact onset, particularly in the absence of a history of a definite injury or sudden appearance of subjective symptoms.