A mattress assembly for a playard has a plurality of support panels coupled to one another and movable relative to one another. The support panels are movable between a generally planar in-use configuration having a top side and a bottom side and a multi-sided storage configuration with an interior space sized to surround a collapsed playard. A mattress pad is detachable from and attachable to the plurality of support panels. The mattress pad lies against the top side of the plurality of support panels and is movable with the plurality of support panels between the in-use configuration and the storage configuration. A plurality of attachment devices are provided for selectively attaching the mattress pad to and detaching the mattress pad from the plurality of support panels.