Klippel-Feil syndrome is a congenital defect in the formation or segmentation of the cervical spine. A wide spectrum of associated anomalies may be present. This heterogeneity has complicated clarification of the genetic causes and management of patient's with congenital vertebral fusion. In this review, we focussed on clinical heterogeneity; radiographic abnormalities and genetic etiology in Klippel-Feil syndrome. We insist on comprehensive evaluation and delineation of diagnostic and prognostic classes.