An electric motor driven adjustable mattress has a shared casing in which at least one flat cushion element of a cushion structure and an electric motor driven adjustable support apparatus for supporting the cushion element are accommodated. The support apparatus has two support parts that are adjustable relative to one another, and that on their sides facing the cushion element are provided with spring elements for elastically resiliently supporting the cushion element. For adjusting the support parts relative to one another, an electric motor driven drive apparatus is accommodated in the shared casing.