In this thesis highly filled and foamed films respectively based on biopolymers are produced and characterized. Base materials are the PLA-Polymers Biomer L9000 (Biomer, Germany) and Bio-Flex 482CF (FKUR, Germany) as well as compounded 70% CaCO3masterbatches. The masterbatches are produced with the calcium carbonat OFM 230-AV and OFM 707-AV from OMYA AG (Switzerland). For the foaming a chemical foaming agent on the base of polypropylene, TRACEL PP3215, from Tramaco GmbH (Germany) is used. At first the highly filled and foamed films respectively with a thickness of 100m and 300m and different filling degree are extruded on the cast film line at the Institute of Polymer Processing. In order to characterize the influence of stretching, the 300m films are simultan, biaxial stretched at Brückner Maschinenbau GmbH (Germany). The unstretched and stretched films of this first serie are characterized via tensile test, dynamic-mechanical-, microscopical-, spectroscopical- and DSC-analyses at the Institute of Materials Science and Testing of Plastics. The examination concerning the thickness are carried out at the Institute of Polymer Processing. It turned out that mechanical properties are highly dependeing on the filling degree, the type of calcium carbonat and the foaming agent, but optical properties are thereof widely independent. Basically primed and foamed PLA-films can be produced on a cast film line without problems.