A mechanism for securing a mattress on a bed foundation is provided. More particularly, the invention relates to a folding mattress-retention mechanism that may compactly fold or be easily removed during shipping or storage. The folding mattress-retention mechanism includes a mattress-support structure, a first hinged attachment, and a second hinged attachment. The mattress-support structure includes a first and second end and may abut a side of a mattress atop a bed foundation. The first and second hinged attachments are coupled to the mattress-support structure at the respective first and second ends and may either affix or removably attach the folding mattress-retention mechanism to the foot, head, or sides of a bed foundation. Further, the hinged attachments may allow for movement, and the folding mattress-retention mechanism may move into and between an operable first position and a stowed second position.