Abstract: A guard for use on a cutting knife of a slitting machine has a body with an opening sized to permit a cutting wheel mounted in the cutting knife to extend through the opening. The body has two ends, with an attachment member associated with each end. The attachment members are shaped to engage receiving members on the cutting knife, so that the guard may be removably attached to the cutting knife. The guard acts as a blade guard, covering the cutting wheel fully when the cutting wheel is retracted, such as during machine set-ups. The opening allows the cutting wheel to be actuated into position during machine operation.