Probiotic strains were isolated from the cheese, turkey and dimity and fermented products (rayb, zeer milk,kariesh cheese), screened for clotting time of  skim milk. The seven effective isolates which clotting skim milk were identified as Bifidobacterium spp (RC1 b8, RC4 b2, FC1b1, SC1 a4, LZ1b8 and LZ1a7)and Lactobacillus spp (S4b1).             The seven effective strains of probiotic bacteria were used in the production of probiotic yoghurt 100%, yoghurt of 50% probiotic bacteria with 50% yoghurt bacteria and compared with the normal yoghurt with 100% normal yoghurt bacteria. The changes in pH, stability of bacteria, and physical properties in probiotic yoghurt 100%, yoghurt of 50% probiotic bacteria  with 50%  yoghurt bacteria  and the normal yoghurt with 100% normal yoghurt bacteria during product's shelf life at 4C for four weaks were also studied.