An artificial intervertebral disc for implantation between two adjacent vertebrae includes superior and inferior shells connected in a ball and socket arrangement. The inferior shell preferably incorporating a convex portion that cooperates with a concave portion on the superior shell. A resilient nucleus is provided within an enclosure defined by the opposing inner surfaces of the shells and biases the shells against each other. The ball portion can be provided in either fixed or slidable arrangement. The superior and inferior shells are also provided with cooperating male and female portions whereby the shells positively engage each other, thereby preventing separation, but allowing any desired articulation there-between. The artificial disc of the invention includes various resistance means for restricting and limiting the range of rotational and translational motion between the shells.