A mechanism for securing a mattress on an automated bed is provided. More particularly, the invention relates to a mattress-retention mechanism for preventing a mattress from moving towards the foot end of a bed during articulation. The mattress-retention mechanism includes a mattress-support structure adapted to support a corner of a mattress, with a portion of the mattress-support structure having a curved interior surface. The mattress-support mechanism also includes a foundation attachment surface for removably attaching the mattress-retention mechanism to the top of a mattress foundation, where the foundation attachment surface is perpendicular to the curved interior surface. The mechanism may include a bedding aperture on the side of the mattress-support structure to accommodate bedding inserted through the bedding aperture. Further, the mechanism may include a side attachment surface for removably attaching the mattress-retention mechanism to a vertical side of the mattress foundation.