An intervertebral disc prosthesis intended to replace a natural intervertebral disc and to restore the normal intervertebral spacing without complete loss of flexibility of the spinal joint. The prosthesis comprises a body of biologically-acceptable material suitably dimensioned and shaped to replace a natural disc. One of the longitudinal ends of the prosthesis has suitable means, e.g. a raised flange, to facilitate handling of the prosthesis and to prevent penetration to an excessive depth into the spinal joint. The other longitudinal end is preferably wedge-shaped to facilitate insertion into the intervertebral space. The superior and inferior surfaces are preferably provided with surface characteristics to produce a "friction-fit" and are convex to correspond to the adjacent vertebral surface. The prosthesis is inexpensive to manufacture and can be implanted quite easily with little danger to the patient. Moreover, the prosthesis maintains at least some of the flexibility of the joint while remaining firmly anchored in place.