As a result of banning of antibiotic growth-promoters in poultry diets, researches about the usage of some other alternative feed additives, such as probiotics are ncreased Probiotics are live microorganisms, and being added to animal feed they suppress pathogenic microorganisms , support beneficial bacteria and absorb some toxic secretions originated from microorganisms, increase secretion of certain digestive enzymes and immune system functions. Thus, after probiotic addition, it is determined that there are an increase in growing, improvement in feed efficiency and in immune response in poultry. However, still there are some points to be clarified such as type of probiotic used in poultry diets, the level of addition, mixing with feed or water and its duration of ussge in diets. In case of determine of mode of action of probiotics by using biotechnological and nuclear techniques, its usage may increase significantly in the future. Consequently, the use of certain natural substances instead of antibiotics in the future is inevitable and probiotics may have increasing importance to meet this demand.