Geosynthetics made from polymeric materials are subjected to either tensile or compressive load throughout their service life in many geotechnical field applications such as reinforced slopes, retaining walls, embankments and waste containments (landfills). Temperature has important effects on tensile strength properties (i.e. ultimate tensile strength, stiffness and toughness) of polymeric geosynthetics, and hence, must properly be evaluated. It is known that polymeric materials consist of viscoelastic properties, and therefore, the degree of loss in strength of polymeric material utilized in a design is a function of temperature variation. The extent of the tensile strain depends on the magnitude of the loading as well as the type of polymer and manufacturing process from which a geosynthetic material is produced. The use of geosynthetics, if not wisely designed and deployed properly in the field (i.e. landfill side slopes), may cause stability problems and jeopardize the integrity of the infrastructure. To this end, tensile strength properties of the two polymeric materials (polyethylene, polycarbonate) from which tension elements of the most composite geosytnthetic multi-layered systems are produced were measured at different temperatures ranging from 20 °C to 70 °C. The tensile tests at various temperatures were performed by using a computer automated universal testing machine insulated for the target test temperatures. The results of the experimental program will be presented along with a further discussion on the type of failure mode (i.e. tension behavior: ductile, brittle) that the polymeric specimens were followed under the application of tensile load. Additionally, a further comparison on ultimate tensile strength properties and tensile extensional (i.e. tensile strain) behavior of the two polymers prior to failure at different temperatures will be provided and the resulting impact of temperature on these tensile strength properties will be discussed. Further, the change in tension failure envelopes of both the polyethylene and the polycarbonate specimens with a change in temperature will be shown.