Due to the availability of its raw resources, gypsum is one of the essential building materials and is widely available in Iraq. The purpose of this study is to improve the mechanical properties of gypsum. In order to investigation of the impact of these, two types of fibers, glass fiber, and polypropylene fibers with specific amounts of each were employed to various gypsum paste formulation. This study has examined the effects of addition of various materials, glass and polypropylene fibers with (1.5,3) % by volume. Compression and modulus of rupture test were then performed. When adding glass fibers to the gypsum, it was found that the optimal percentage of addition was 1.5% as a volumetric percentage of the gypsum as this percentage of addition gives a significant increase in the modulus of rupture by 45.7% and slight development of compressive strength by 13.07%. The mixtures with polypropylene fibers, it was found that the optimal percentage of addition was also 1.5% as a volumetric percentage of the gypsum. This percentage of addition gives a significant increase in the modulus of rupture about 30.63% compared to other simple development compressive strength by 3.01%.