According to a method for producing support structures in motor vehicles, especially parts of a motor vehicle seat, at least one base element (BE) consisting of a thermoplastic material with a fabric back stay, especially a glass fiber reinforced thermoplastic (GMT) is inserted into tool (8) to form a support structure base (TB), is thermoplastically deformed and is subjected, at the same time or subsequently, to at least one additional process for reinforcing the support structure base (TB), integrally forming at least one additional structure (ZS), and integration of functional parts or integration of interfaces for additional components into the support structure (TB).