This work aimed: To enhance production of antioxidant from S.cerevisae without affecting bakery properties of cells and production of selenium yeast with keeping the balance between incorporation of selenium and optimal growth without affecting bakery properties of cells. These cells could be added to dough for baking process and increase level antioxidant in bread. So, this work is divided into three main parts: Part I: Propagation and behavior of baker's yeast Part II: Improvement of antioxidants: Part III: Preparation and evaluation of selenium yeast.