This diploma thesis is a research about natural materials that can be used in the building of automobiles. Due to the current CO2 situation and the necessity of saving raw materials, the use of renewable raw materials in automotive skeletons should be considered. To reach these targets, composites made of natural fibre-reinforced plastics are very popular among vehicle manufacturers. Big advantages are their mechanical qualities in combination with low weight and easy process ability. This leads to the consideration to use natural fibre-reinforced plastics in carcases of vehicles. This diploma thesis is split into three parts. The first part is primarily dealing with present availability of renewable materials. The second part assesses possibilities of using these materials in carcases, as well as pre-sorting the possible materials and components. Composites made of linen and hemp fabrics have turned out to be suitable for testing. Because mechanical properties of these fabrics were missing, composite sheets had to be built. In a tensile test, mechanical properties were determined. The results were prepared by using classical laminate theory in order to determine specific values for final simulation. The result of classical laminate theory was positive. Finally, these composites made of linen and hemp fabrics were simulated in application. The application of these materials was tested on the FIAT Bravo tunnel. From the technical point of view the results could be categorized as being ok in terms of global static as well as dynamic rigidity.