The subject of this thesis is the numerical analysis of an ultra-sport car frame. More precisely, the numerical analysis deals with the calculation of the frame torsional rigidity or stiffness. The frame belongs to the Concept One ultra-sport car produced by the car manufacturer Rimac Automobili. The preface briefly describes the problems engineers have to deal today. Then, the company Rimac Automobili, a leader in development and manufacturing of electric ultra-sport cars, is described. Also a short review of their production range and detailed specifications about the Concept One car are given. The company provided a 3D CAD model of the car frame for the numerical analysis. A brief history of the development of car frame and desired characteristics are given as a separate chapter within the introduction. The most desired characteristic is the cars rigidity, as a result of frame stiffness. The stiffness is divided in three components, the axial, the flexural and torsional component. Among them, torsional stiffness is a very significant characteristic that shows us whether the car is designed correctly, has less stiffness than desired or required. Also, stiffness is very important for steering and suspension settings because it directly affects the vehicle driveability. In the third chapter a detailed description of the finite element analysis is given. Finite element analysis is very popular for calculations thanks to available computer technology and was used to make calculations for this thesis. Finite element analysis is integrated in appropriate computer software that uses a lot of hardware resources, such as RAM memory and processor speed. For the analysis one must verify if the available elements are suitable to simulate a real life problem. A verification has been made to ensure that beam and shell elements given in the software ANSYS are suitable to use for analysis of torsional stiffness. Furthermore, the process of creating the analysis model is described. The first step was to generate the vehicle frame using lines and surfaces in the software CATIA. Next, this frame model was imported in ANSYS software, where tube section properties for each tube and sheet reinforcements thickness were defined. The obtained model was discretized with finite elements, boundary conditions were applied such as torsional moment and displacement suppression. Five meshes (ranging from coarse to very fine) were made and tested to obtain displacement results. In chapter five the results were evaluated and a conclusion has been drawn.