Sliding shelves (2a, 2b, 4a, 4b) are provided for refrigerators and freezers, which have a movement along side support guides (1) that enable the retracting, fitting and bounce of the shelves, allowing the choice of different configurations for the inner space of the household appliance, according to the area to be used to store food. This configuration enables different arrangement of shelves, including: extended shelves, retracted shelves, vertically bounced shelves, or even, in an associated form, an extended shelf and another bounced one.