The presented diploma thesis is focused on testing composite samples reinforced with carbon fibers and their subsequent analysis and evaluation of mechanical properties of composite materials at different temperature conditions. The theoretical part of the thesis generally describes composite materials, their brief characteristics, the distribution of composite materials and their properties. Mechanical tests are also briefly described in this section. In the experimental part, the results of mechanical tests of composite samples at different temperatures are analyzed and compared. There is also described the production of samples and the method of performing the tests, namely the bending test, the tensile test and the impact bending test.