Additive manufacturing is a production process which started developing in 1980s but became more popular and common in the last decade. Using computer aided design (CAD) or 3D object scanners, additive manufacturing allows for the creation of objects with precise geometric shapes. Also, by using different materials it is possible to achieve wanted mechanical properties. These are some of the reasons why 3D printing is being used in biomedical engineering. Since 3D printing is relatively new technology, new materials are being used so it's necessary to identify their properties. Most used experiment for identifying material properties is the uniaxial tensile test. Some of the properties that are measured and determined via a tensile test are ultimate tensile strength, breaking strength and Young's modulus. Planar biaxial tensile tests determine the mechanical properties of the test sample that experiences tensile biaxial states of stress and its test data is superior to uniaxial data if the material experiences stress in complex multiaxial configurations. While examining the cruciform sample a stress concentration occurs in specific area and the specimen does not deform to a desired level when it has fractured in other areas. The main goal in this final paper was to increase the stretch ratio in homogenous part of the specimen so new, optimized specimen must have been designed. Different geometries of the cruciform specimen and their impact on the results are shown in this final paper. Catia V5R21 software was used to create the CAD model, while numerical analyzes were performed in the Abaqus software package.