In this work a technique is proposed to use bending test in order to determine the tensile and the compressive moduli of plastic sheets as well as polymer composites. A two-component free ends beam deflected in a three point cantilever is used to determine tensile and compressive moduli. Using small deflection equations and the theory of two-component beam, tensile and compressive moduli are then determined via computer program. The beam is composed of two components; spring steel and polymeric strip of the same width. These two components are bonded together with special glue. Two different types of material sheets were tested. The results show that both materials have different tensile and compressive modulus. To verify the model, uniaxial tensile tests were also performed. Taking the values of uniaxial tensile tests as reference showed acceptable accuracy at the proposed method.