The present disclosure provides a cylinder deactivation engine which is configured to prevent abrasion on a pad portion of a valve opening/closing unit and improves reliability of the cylinder deactivation. The cylinder deactivation engine selectively performing deactivation of a cylinder may include: a cylinder deactivation apparatus including an inner body which contacts with a cam formed at a camshaft and makes a lever motion by rotation of the camshaft; and an outer body which moves together with the inner body by selectively latching to the inner body so as to open/close a valve; and a stopper integrally formed with a cam carrier disposed to surround a part of a lower portion of the camshaft and disposed between the camshaft and the outer body so as to function as a stopper for blocking the outer body which is pushed toward the camshaft by the valve.